Rozprawy doktorskie na temat „Feeds”

Thesis (MScAgric)--University of Stellenbosch, 2002.
ENGLISH ABSTRACT: Starch is the main component of cereal grains and is usually the primary energy source for pigs and poultry. Feed manufacturing can adopt several measures, including physical treatments such as milling or pelleting and other techniques, such as enzyme treatment, to disrupt cell structure. Grinding and pelleting are the most common food processing methods used for pigs. However, pelleting of complete balanced feeds is no longer such an economical proposition due to rising energy and equipment costs; therefore this cost has to be outweighed by an increased production efficiency. It has been known for many years that grinding is an essential prerequisite for the satisfactory blending of the ingredients of a multi-component food. Feed cost represents the major item in the cost of animal production. Without doubt, research and production efforts will continue to refine feed processing techniques to reduce the cost of feed and to increase the value of feed for a target animal. The possibilities for improvements in feed are endless; however the cost of each innovation must be carefully weighed against demonstrated improvements in animal performance. Experiment 1: The effect of feed processing techniques on weanling pig growth-performance The effects of processing of the carbohydrate source and the feed on growth performance of commercial Landrace x Large White piglets (n=480) weaned at 28 ± 2 d were investigated. Two processing combinations of the carbohydrate source were used with 3 processing conditions of the diet in a 2 x 3 factorial design. The pigs were blocked by weight (7.196 ± 2.03 kg BW) and then allotted randomly to 1 of 6 dietary treatments. Ten pens of 8 piglets each were fed with each dietary treatment. The two main processing conditions of the carbohydrate source were raw or extruded maize and the 3 processing conditions of the diet was meal or pelleted or extruded. No carbohydrate processing x diet processing interactions were observed (P > 0.05) for ADG, ADFI or FeR. In this experiment, extrusion of the maize led to an significant decrease in FeR efficiency (P < 0.05) (1.57 vs. 1.42) when compared to a raw maize diet. Pelleting a diet had no significant effect (P > 0.05) on ADG but tended to decrease ADFI (P < 0.07) and significantly improve FeR efficiency (1.49 vs. 1.66) when compared to a meal diet. Extruding the whole diet did not have any significant (P > 0.05) effect on ADG but tended to decrease ADFI (P < 0.07) and gave an significant improvement in FeR when compared to a meal diet (1.34 vs. 1.66). This processing technique also gave a significant improvement (P < 0.01) in FeR when compared to a pelleted diet (1.34 vs. 1.49). Experiment 2: The effect of pig feed processing conditions on pig metabolism parameters The effects of processing of the carbohydrate source and the diet on certain metabolism and production parameters of commercial Landrace x Large White pigs (n=24) were investigated. Two processing combinations of the carbohydrate source were used with 3 processing combinations in a 2 x 3 factorial design. Six diets were formulated on an iso-nutrient basis (14.48 MJ/kg metabolizable energy (ME), 23.01 crude protein (CP), 1.092% lysine, 0.742% methionine and cystine and 0.271% tryptophan on a DM basis). The pigs were blocked by weight (26.02 ± 0.25 kg BW) and then allotted randomly to I of 6 dietary treatments. The carbohydrate source was raw or extruded maize and the diets was meal or pelleted or extruded. No carbohydrate processing x diet feed form interactions were observed (P > 0.05) for dry matter intake (DMI), dry matter digestible energy (DE), Nitrogen (N) or dry matter intake (DMI). In a metabolism and nitrogen (N) balance study, apparent N digestibility, digestible energy and metabolizable energy contents were found not to be significantly (P > 0.05) influenced by carbohydrate or diet processing.
AFRIKAANSE OPSOMMING: Stysel is die hoof komponent in grane en is gewoonlik die primêre verskaffer van energie vir varke en pluimvee. Voermeulens kan verskeie metodes implementeer, insluitend fisiese behandeling soos bv. maal, verpilling en ensiem behandelings, om sel struktuur te verander. Maal en verpilling is die mees algemene prosessering metodes wat vir varkvoer gebruik word. Maar, verpilling van totaal geballanseerde voere is nie meer so ekonomies geregverdig nie as gevolg van stygende energie en masjinerie koste. Daarom moet die koste van voervervaardiging oorbrug word deur 'n verhoogde produksiedoeltreffendheid. Dit is al lankal bekend dat maal 'n voorvereiste is vir effektiewe vermenging van grondstowwe van 'n multi-komponent voer. Voerkoste verteenwoordig die hoof item van die koste van intesiewe diereproduksie. Voedingskudiges sal sonder twyfel voortgaan om voerprosessering te verfyn om so die koste van die rantsoen te verlaag en om die waarde van die rantsoen te verhoog vir die dier. Die moontlikhede is veelvuldig, maar die koste van elke ontwikkeling moet opgeweeg word teen verhoogde diereproduksie. Eksperiment 1: Die effek van voerprosesserings-tegnieke op speenvark groei en produksie 'n Proef is uitgevoer om die prosesseringseffek van 'n koolhidraat bron en voer op die groei van Landras x Groot Wit speenvarke (n=480) wat gespeen is op 28 ± 2 d te bepaal. Twee prosesserings-kombinasies van die koolhidraat bron en drie prosesserings-kondisies van die dieet is in 'n 2 x 3 faktoriaal ontwerp uitgevoer. Die varkies is geblok volgens massa (oorspronklik 7.196 kg ± 2 kg) en toe ewekansig in I van 6 dieët behandelings ingedeel. Die proefdiëte is vir lO hokke varkies gevoer, elke hok het 8 varkies in gehad. Die twee hoof prosesserings-kondisies van die koolhidraat bron was rou of gaar mielies en die drie prosesserings-kondisies van die dieët was meelof gaar of geëkstrueer. Geen koolhidraat prosesserings x dieët prosesserings interaksie van die dieët was opgemerk (P > 0.05) vir gemiddelde daaglikse toename (GOT), gemiddelde daaglikse voer inname (GDVI) of voer omset doeltreffendheid (VOD) nie. In die eksperiment was die VOD van die geëkstrueerde mielie dieët, statisties betekenisvol laer (P < 0.05) (1.57 vs.1.42) as die rou mielie dieët. Verpilling van die dieët het geen statisties betekenisvolle effek (P > 0.05) op GDV! gehad nie, maar die VOD was statisties betekenisvol (P < 0.05) beter (1.49 vs. 1.66) wanneer dit met die meel dieët vergelyk word. Ekstrusie van die dieët het geen statisties betekenisvolle effek op GOT en GOVI gehad nie, maar die VOD was statisties betekenisvol (P < 0.05) beter wanneer dit met die meel (1.34 vs. 1.66) en verpilde dieët (1.34 vs 1.49) vergelyk word. Eksperiment 2: Die effek van voer prosessering op vark metabolisme parameters 'n Eksperiment is uitgevoer op Landras x Groot Wit bere (n=24) om die effek van prosessering van 'n koolhidraat bron en voer te bepaal. Twee prosesserings-kombinasies van die koolhidraat bron en drie prosesserings-kondisies van die dieët is in 'n 2 x 3 faktoriaal ontwerp uitgevoer. Ses diëte is geformuleer op 'n iso-nutriënt basis (14.48 MJ/kg metaboliseerbare energie (ME), 23.01 ru-proteïen (RP), 1.092% lisien, 0.742% metionien and sistien en 0.271 % tryptofaan op 'n droeë materiaal (DM) basis). Die varke is geblok volgens massa en ewekansig aan 1 van 6 diëte toegeken. Die koolhidraat bron was gaar of rou mielies en die diëte was meel, verpil of geëkstrueer. Geen koolhidraat-prosessering x dieet interaksie is opgemerk (P > 0.05) nie. In 'n metabolisme en stikstof (N) balans-studie is daar gevind dat DM verteerbaarheid, skynbare N verteerbaarheid, verteerbare energie (GE) en ME inhoud nie beduidend deur die behandelings beïnvloed word nie.

Thesis (M.S.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on January 16, 2008) Includes bibliographical references.

In the recent years, there has been a rapid development in the field of fisheries especially with reference to aquaculture. India has vast fisheries resources with a total EEZ (Exclusive Economic Zone) of 2.02 million square kilometers and a coastline of 8047 kilometers. The total riverine length is above 29,000 square kilometers. The lentic water bodies include lakes, ponds, tanks, reservoirs, bheels, bans, jheels,etc,which are estimated to be nearly 1.29 lakh hectares in area. The rivers upon joining the sea form large areas of brackish water estuaries. The area suitable for brackishwater fish farming is around 2 million hectares. These form a tremendous resource for fisheries in the country. The marine environment produces around 2.6 million tonnes of fish, comprised of different variety of fishes, crustaceans and mollusks. The inland water resources produce around 2.3 million tonne of fish. Eventhough the current inland production lags behind the marine production there has been a tremendous increase in the annual growth rate primarily due to aquaculture.

Traditional passive surveillance is proving ineffective as the number of available cameras for an operator often exceeds the operators ability to monitor them. Furthermore, monitoring surveillance cameras requires a focus that operators can only uphold for a short amount of time. Algorithms for automatic detection of anomalies in video surveillance feeds are thereby constructed and presented in this thesis by using hidden Markov models (HMM) and a Gaussian mixture probability hypothesis density (GM-PHD) filter. Four different models are created and evaluated using the PETS2009 dataset and a simulated dataset from FOI. The three first models are created to model normal behaviour of crowds in order to detect anomalies. The first uses only one HMM to model all observed behaviours. The second model uses two different HMMs, created by manually splitting the observations in the training set into two parts corresponding to different behaviours. This model does not perform as well as the first model. The third model is attained by clustering the observations in the training dataset, using dynamic time warping (DTW) and z-scores, and creating a separate HMM for each cluster. This model is regarded as the most efficient anomaly detector. The last model uses information from all crowds in the surveilled scene but does not perform well enough to be used to detect anomalies.
Traditionell övervakning är ofta ineffektiv i och med att antalet tillgängliga övervakningskameror ofta överstiger en operatörs förmåga att bevaka dessa. Vidare kräver övervakning ett fokus som en operatör endast klarar av att upprätthålla under en kort tidsperiod. I detta arbete har därför algoritmer för automatisk anomalidetektion i övervakningskameror skapats, med hjälp hidden Markov models (HMM) samt ett Gaussian mixture probability hypothesis density (GM-PHD) filter. Fyra olika modeller har implementerats och utvärderats med hjälp av PETS2009 datasetet samt ett simulerat dataset från FOI. De tre första modellerna är skapade för att modellera normalt beteende bland folksamlingar och kan därefter användas för att upptäcka anomalier. Den första modellen använder sig av endast en HMM för att modellera olika beteenden. Den andra modellen använder sig av två olika HMMer, skapade genom att manuellt dela upp observationerna i träningssetet i två delar så att dessa motsvarar olika beteenden. Denna modell fungerar inte lika bra som den första modellen. Den tredje modellen har konstruerats genom att klustra samtliga observationer, med hjälp av dynamic time warping (DTW) och zscores, därefter skapas en HMM för varje kluster. Denna modell anses vara den mest effektiva anomalidetektorn. Den sista modellen använder information från alla grupper i det bevakade området men fungerar inte tillräckligt bra för att kunna upptäcka anomalier.

With over 0.25 billion web pages hosted in the World Wide Web, it is virtually impossible to navigate through the Internet. Many applications try to help users achieve this task. For example, search engines build indexes to make the entire World Wide Web searchable, and news curators allow users to browse topics of interest on different structured sites. One problem that arises for these applications and others with similar goals is identifying documents with similar contents. This helps the applications show users documents with unique contents as well as group various similar documents under similar topics. There has been a lot of effort into algorithms that can achieve that task. Prior research include Yang, Pierce & Carbonell (1998) research where they looked at the problem of identifying news events exploiting chronology order, Nallapati, et al (2004) research who built a dependency model for news events and Shah & Elbahesh (2004) research where they used Jaccard coefficient to generate a flat list of topics. This research will identify training and testing datasets, and it will train and evaluate (Pera & Ng) algorithm. The chosen algorithm is a hierarchical clustering algorithm that incorporates many of the ideas researched earlier. In evaluation phase, error will be measured in the ratio of miss-categorized documents to the total number of documents. The research will show error can be as low as 0.03 with a model built on a single node processing 1000 random distinct documents. In evaluation of the algorithm, the experiments will show that (Pera & Ng)’s fuzzy equivalence algorithm does produce acceptable results when compared to Google News as a reference. The algorithm, however, requires a huge amount of memory to hold the trained model. This renders it not suitable to run on portable devices.

Thesis (Honors)--Ohio State University, 2007.
Title from first page of PDF file. Document formatted into pages: contains 18 p.; also includes graphics. Includes bibliographical references (p. 18). Available online via Ohio State University's Knowledge Bank.

Clinoptilolite is a zeolite and an aluminosilicate that can be fed to swine in order to reduce nutrients being excreted because of their molecular sieving properties, high cation exchange capacities, and a high affinity for the ammonium ion (NH4+). Preliminary research has been carried out on utilizing zeolite's unique characteristics for dietary supplementation for livestock, however much of this research is limited and is still in its infancy.
The results from this study show that the zeolite with a particle size distribution either >250 mum or mixed (50% particles greater and smaller than 250 mum) adsorbed the most NH4+. Macro mineral and heavy metal release was similar among all particle size distributions tested, but varied between sources of zeolite. Handling properties of zeolite were not affected by moisture content or particle size. The feed trial indicated that zeolite supplementation, combined with a low crude protein and energy diet and at an inclusion level of 4%, showed potential as a feed additive in swine diets for the purposes of nutrient reduction. Nevertheless, zeolite seemed to have a greater impact on energy ingestion, as compared to crude protein. Even at 6% zeolite inclusion in the feed, hog muscle, kidney and liver tissues showed no significant increase in heavy metal contents, as compared to those fed any zeolite.

The rapid growth of Canadian pork industry has been challenged by its negative impact on the environment. To find an economical and promising solution to the environmental problems, 4% zeolite (90%+ clinoptilolite) were supplemented to a regular (100% crude protein (CP) and energy) or low CP and energy (90% CP and 90% energy or 90% CP and 85% energy) grower pig diets. Twenty male and twenty-four female grower pigs were used in two feeding experiments respectively, followed by a metabolic test with three batches of animals repeated to determine the metabolic effects of zeolite supplementation. Pig performance (body weight gain, daily feed intake and feed conversion ratio), and metabolic parameters (manure mass, feed intake, protein and energy conversion, as well as dry feed and organic matter retention) were evaluated. Zeolite supplementation at 4% to a regular diet for grower pigs had a positive but not significant (P > 0.05) effect on all pig performance and metabolic parameters, compared to the regular diet without zeolite. Among 4 rations, pigs on a regular diet with 4% zeolite performed consistently best throughout the entire trail, with decreased average daily consumption and reduced amount of feces, increased feed and organic matter retention in the gastrointestinal tract, improved feed as well as protein and energy conversion, and enhanced body weight gain. Moreover, zeolite supplementation at 4%, with 90% CP and 90% energy in grower pig diets, improved feed and protein and energy conversion rate, and increased body weight gain, when compared to those of pigs fed a regular diet without zeolite. However, a diet of 90% of CP and 85% of energy with 4% zeolite significantly (P < 0.05) increased feed consumption and the amount of feces produced, and decreased feed and organic matter retention in the gastrointestinal tract, thus reducing feed conversion rate. Therefore, 4% zeolite supplementation to the regular or low CP and energy (90% C
Key words. Clinoptilolite, Pig, Pig Performance, Metabolic Parameter.

A replicated 3 x 3 latin square design (3 periods and 6 rumen fistulated steers) was utilized to investigate the effect of dietary concentrate levels (30, 60 and 90%) on the in situ disappearance of dry matter (ISDMD) and neutral detergent fiber (NDF) and kinetics of fiber digestion of alfalfa hay, wheat straw and steam processed and flaked milo (SPFM). Concentrate levels of 30 and 60% did not affect (P > .05) ISDMD or NDF disappearance from any of the substrates. However, ISDMD and NDF disappearance of all substrates were depressed (P < .05) by the 90% concentrate diet. The degradation of the potentially digestible fiber in these substrates followed first order kinetics at all concentrate levels. Fiber digestion kinetics were not affected (P > .05) by dietary concentrate levels of 30 or 60%. Incubation of substrates in animals receiving the 90% concentrate diet resulted in lower potential extent of digestion (P > .05) and decreased rate of degradation (P > .05) for all substrates. However, digestion was not complete even after incubations of 168-h, and thus, it is possible that the potential extent of digestion was underestimated. For all substrates lag time of digestion appeared to increase in the 90% concentrate diet. However, influx of NDF-like material into the bag during incubation makes the validity of the lag times obtained in situ questionable. Ruminal pH was depressed in animals consuming the 90% concentrate diet and could be at least one of the factors responsible for the decreased (P > .05) fiber digestibility in this diet. Mean ruminal pH of 6.5 (30 and 60% concentrate diets) did not depress (P > .05) fiber digestibility while a mean pH of 6.2 resulted in a lower (P > .05) fiber digestibility in the rumen.

Investigations into the poor recovery of sulphadimidine from medicated animal feeds have shown that irreversible drug-feed binding, and not drug degradation, is responsible for the poor recoveries. The experimental work involved the novel use of C-sulphadimidine in analytical studies and in autoradiography of C-sulphadimidine-bound feed. The latter showed that the drug was not bound preferentially to specific feed constituents but was widely distributed on nearly all the feed particles. Further work on sulphadimidine recovery from feeds demonstrated an inverse relationship between drug recovery and feed moisture content. The role of moisture in the binding mechanism was then considered, and experiments conducted on the adsorption of moisture by feeds showed that the rate controlling mechanism was diffusion. A hypothesis is presented in which sulphadimidine is partially dissolved by the moisture in the feed and the resulting solution then diffuses into the internal regions of the feed particles via pores and cracks in the constituent particles. The deep penetration of the drug into the feed prevents the drug from being recovered by the extraction solution. Experimental evidence was found to support this hypothesis. Experimental work also investigated the causes of poor recoveries of sulphadiazine, trimethoprim and dinitolmide.

This thesis investigates optical feed methods for phased array antennas. The technical and practical limitations are analyzed and an optimum design is determined. This optimum optical feed is a two-beam interferometric approach which uses acoustooptic phase control. The theory is derived; a computer model is developed; and the limitations are determined. Design modifications are suggested which reduce limitations and greatly extend the range of applications.
Master of Science

Thesis (MSc)--Stellenbosch University, 2000.
ENGLISH ABSTRACT: South Africa, like many other developing countries throughout the world, has a rapidly growing human population, resulting in a consequent increased demand for food. Ironically, this increased food supply has to be produced on a smaller area of available agricultural land, which means that agricultural production processes have to become more efficient. Furthermore, the majority of the people in these countries are unschooled and poverty is a common phenomenon. Therefore, animal scientists are faced with the challenge and the responsibility to provide affordable, high quality food to these people. One way of reaching this objective is to improve the utilisation of low-quality, high roughage feedstuffs like crop residues and dry natural grass pastures. In the winter rainfall area of South Africa alone, about 460 000 ha of wheat straw are annually available. The ruminant animal has the ability to utilise the relatively unavailable energy (cellulose, hemi-cellulose and pectin) in the fibre component of these low-quality forages. Unfortunately, various factors, of which a N deficiency is the pre-dominant one, limit the utilisation of these feedstuffs. If the ability of the ruminant to utilise low-quality, fibrous energy sources is improved, these abundantly available and relatively inexpensive crop residues and natural pastures can be converted into high quality protein food for human consumption. Therefore, in order to rectify the N deficiency caused by these low-quality forages, the supplemental N requirement to optimise the fermentation and digestive processes of the ruminant animal has to be determined. The first study was conducted to determine the supplemental rumen degradable protein (RDP) requirement, to maximise the digestible organic matter intake (DOMI) of Dohne Merino sheep fed wheat straw. Keeping the high cost of natural protein supplementation in mind, the purpose of the second study was to determine the amount of true protein that can be replaced by nonprotein nitrogen (NPN) in RDP supplements fed to Dohne Merino sheep consuming wheat straw. In both trials animals had ad libitum access to low-quality wheat straw (3.2% CP; 74.2% NDF) and water. In the first trial, RDP (calsium caseinate: 90% CP; 100% rumen degradable) was intraruminally administered at 07hOOand 19hOO,at the following levels: 0, 40,80, 120 and 160 gld. Intake, fermentation and digestion were monitored to determine the RDP requirement to maximise DOM!. Digestible organic matter (OM) intake displayed a quadratic increase with elevated amounts of RDP (P < .01), and was maximised at an estimated 3.15 g RDPlkg BW·75 or 11.6% of DOM. Forage OM intake tended to increase quadratically (P = .15) with higher RDP levels. Microbial nitrogen (MN) flow to the duodenum and microbial efficiency increased quadratically (P ~ .04) and fluid dilution rate tended to increase in a quadratic manner (P = .15) with increased RDP supplementation levels. Rumina! ammonia nitrogen (NH3-N) and total volatile fatty acid (VFA) concentrations increased linearly (P ~ .07), while rumen pH exhibited a variable response to increased RDP levels (cubic; P = .08). Increasing RDP supplementation to Dohne Merino wethers consuming wheat straw, generally enhanced forage utilisation and DOM!. In the second trial, urea replaced different levels of casein N on an isonitrogenous basis, ranging from 0 - 100%. Since true protein is much more expensive than urea, the purpose of this study was to determine the maximum natural protein level that can be replaced by urea in RDP supplements, without adversely affecting intake and/or fermentation and digestive processes. The control treatment provided all of the RDP in the form of calcium caseinate (90% CP; 100% rumen degradable). The percentages of supplemental RDP from urea in the other treatments were 25, 50, 75 and 100%. The 100% urea treatment was balanced with maize starch to contain 40% CP and all other treatments received the same amount (150 gld) of starch. Intake of forage OM showed a weak decreasing trend (linear; P = .16) with increasing urea levels. Ruminal digestibilities of OM and NDF were not affected (P ;;::.:18) by urea level. Increasing urea levels resulted in linearly reduced total tract OM and NDF digestibilities (P ~ .10). As a result, DOMI declined (linear; P < .01) with increasing proportions of urea. Effects of increasing urea proportions on duodenal N flow, microbial efficiency and fluid dilution rate were minimal. Ruminal NH3-N tended to increase quadratically with increasing urea levels (P = .l4). Total VFA concentration decreased linearly (P = .03), while rumen pH increased in a linear manner (P = .08) with increasing urea proportions. Branched-chain volatile fatty acids (BCVFA's) and valerate decreased linearly (P ~ .05) with increasing urea levels, while other VFA's and the acetate:propionate ratio were generally not affected by treatment (P ;;:::.16). It appears as though ruminal and total tract OM and NDF digestibility criteria, as well as DOMI reached maximum values at substituting 25% of casein for urea. It is therefore concluded that replacing 25% of casein with urea in RDP supplements, will maintain effective utilisation of low-quality forages by sheep.
AFRIKAANSE OPSOMMING: Ontwikkelende lande, insluitend Suid-Afrika, word gekenmerk deur 'n vmmge bevolkingsaanwas. Dit lei tot 'n verhoogde vraag na voedsel, wat op 'n gevolglik kleinerwordende beskikbare kommersiële lanbbou-area geproduseer moet word. Die doeltreffendheid van produksieprosesse in die landbousektor moet dus noodgedwonge verbeter word. Die oorgrootte meerderheid van die bevolkings in ontwikkelende lande is ongeletterd en armoede en hongersnood is soms 'n algemene verskynsel. Veekundiges word dus gekonfronteer met die uitdaging en verantwoordelikheid om bekostigbare, hoë kwaliteit voedsel aan hierdie mense te voorsien. Een van die mees doeltreffende metodes om hierdie probleem aan te spreek, is om die benutting van lae kwaliteit, hoë-vesel voerbronne, bv. oesreste en droë grasweidings te verhoog. In die winterreënstreek van Suid-Afrika alleen, is 460 000 ha koringstrooi jaarliks beskikbaar. Herkouers beskik oor die besondere vermoë om die relatief onbeskikbare energie (sellulose, hemi-sellulose en pektien) in die veselkomponent van hierdie lae kwaliteit voere te benut. Verskeie faktore, waarvan 'n N-tekort die mees prominente is, beperk egter die benutting van hierdie voerbronne. Die uitdaging is dus om die herkouer se vermoë om hierdie voere te benut, te optimaliseer. Sodoende word 'n geredelik beskikbare, onderbenutte en relatief goedkoop voerbron omgeskakel in hoë kwaliteit proteïen vir menslike gebruik. Die N-aanvullingsbehoefte om die fermentasie- en verteringsprosesse van die herkouerdier te optimaliseer moet dus bepaal word, sodat die N-tekort in herkouers, wat soortgelyke weidings benut, reggestel kan word. Gevolglik was die doel met die eerste proef om die behoefte aan rumen degradeerbare proteïen-(RDP)-aanvulling, vir die maksimum inname van verteerbare organiese materiaal (VOM) van Dohne Merino skape wat koringstrooi ontvang, te bepaal. Weens die hoë koste van natuurlike proteïenaanvulling, was die doel met die tweede proef om die hoeveelheid ware proteïen in RDP-aanvullings, vir Dohne Merino skape wat koringstrooi ontvang, wat met nie-proteïen stikstof (NPN) vervang kan word, te bepaal. In beide eksperimente het die diere ad libitum toegang tot koringstrooi (3.2% RP; 74.2% NBV) en water gehad. In die eerste proefis RDP (kalsiumkaseïnaat; 90% RP; 100% rumen degradeerbaar) teen 07hOOen 19hOOintraruminaal toegedien, teen die volgende peile: 0, 40, 80, 120 en 160 gld. Inname, fermentasie en vertering is gemonitor om die RDP behoefte vir die maksimum inname van VOM te bepaal. Verteerbare OM-inname het 'n stygende kwadratiese tendens (P < .01) getoon met verhoogde RDP-peile en het 'n maksimum bereik by 'n aanvullingspeil van 3.15 g RDPlkg metaboliese liggaamsmassa (LM·75 ) of 11.6% van VOM. Organiese materiaalinname vanaf koringstrooi het geneig om kwadraties toe te neem (P = .15) met verhoogde RDP-peile. Mikrobiese stikstof-(MN)-vloei na die duodenum en mikrobiese effektiwiteit het kwadraties toegeneem (P :::;.;04) en vloeistof deurvloeitempo het 'n neiging vir 'n kwadratiese toename (P = .15) met verhoogde RDPpeile getoon. Rumen-ammoniakstikstof (NH3-N) en vlugtige vetsuur-(VVS)-konsentrasies het lineêr toegeneem (P :::;.;07), terwyl rumen pH 'n wisselende reaksie (kubies; P = .08) met stygende RDP-peile getoon het. Verteerbare OM-inname en benutting van koringstrooi is verbeter deur stygende peile van RDP aanvulling by Dohne Merino hamels. In die tweede proef is kaseïen op 'n iso-stikstof basis met verskillende ureumpeile, vanaf o - 100%, vervang. Omdat ureum baie goedkoper is as natuurlike proteïen, was die doel van die tweede proef om die hoeveelheid natuurlike proteïen in RDP-aanvullings te bepaal wat met ureum vervang kan word, sonder om inname, fermentasie en vertering te benadeel. Die kontrolebehandeling het 100% van die RDP in die vorm van kalsiumkaseïnaat (90% RP; 100% rumen degradeerbaar) voorsien, terwyl ureum in die ander behandelings onderskeidelik 25, 50, 75 en 100% van die kaseïen-N vervang het. Die 100% ureumbehandeling is met mieliestysel tot 40% RP gebalanseer en dieselfde hoeveelheid stysel (150 gld) is by al die ander behandelings ingesluit, om moontlike effekte van stysel op rumenfermentasie te elimineer. Organiese materiaalinname vanafkoringstrooi het 'n swak dalende tendens getoon met stygende ureum insluitingsvlakke (lineêr; P = .16). Rumenverteerbaarheid van OM en neutraal bestande vesel (NBV) is nie deur die ureumpeil beïnvloed nie (P ;;:: .18). Toenemende ureumpeile het gelei tot 'n lineêre afname in totale kanaal OM en NBVverteerbaarheid (P ~ .10). Gevolglik het VOM inname lineêr afgeneem (P < .01) met stygende ureum insluitingspeile. Die effek van behandeling op duodenale N-vloei, mikrobiese effektiwiteit en vloeistof deurvloeitempo was minimaal. Rumenammoniakstikstof-( NH3-N)-konsentrasie het 'n stygende kwadratiese tendens getoon (P = .14) met toenemende ureum peile. Totale vlugtige vetsuur-(VVS)-konsentrasies het lineêr gedaal (P = .03), terwyl rumen pH lineêr toegeneem het (P = .08) met stygende ureum insluitingsvlakke. Vertakte ketting VVS' e en valeriaansuurkonsentrasies het lineêr gedaal (P ~ .05) met stygende ureumpeile, terwyl die ander VVS' e en die asynsuur:propioonsuurverhouding oor die algemeen nie deur behandeling beïnvloed N; nie (P ;;:: .16). Dit blyk asof VOM inname, sowel as rumen- en totale kanaal verteerbaarheidsmaatstawwe, by 25% vervanging van kaseïen-N met ureum-N 'n maksimum bereik het. Die gevolgtrekking is gemaak dat die doeltreffende benutting van lae kwaliteit ruvoere deur skape, gehandhaaf sal word deur 25% van die ware proteïen in RDP-aanvullings met ureum te vervang.

This study was designed to provide information on some of the factors affecting voluntary consumption and digestibility of forages by sheep. A wet sieving procedure was used to determine particle size distribution in the reticulo-rumen, omasum and abomasum of sheep fed 100 % prebloom alfalfa or 100 % second-cut Altai wild ryegrass hays or mixtures of these with tall wheatgrass or Altai wild ryegrass straws. The study also compared second-cut Altai wild ryegrass and prebloom alfalfa as components in an all forage diet for sheep. Each diet was fed ad libitum to eight Romanov x Western whiteface wether lambs weighing 22 to 25 kg during the intake and digestibility trials. For the determination of particle size distribution, the animals were slaughtered at 12, 24, 36, and 48 hours after feed removal and the contents of the reticulo-rumen, omasum and abomasum sampled. Five different methods of describing digesta particle size distribution were compared as to their ability to predict voluntary intake and digestibility of the forages by sheep. The best method for expressing particle size distribution in the reticulo-rumen in terms of ability to predict dry matter digestibility (DMD) was the proportion of soluble dry matter in total dry matter (PSDM). A significant (P< 0.05) correlation (r = 0.84) between PSDM and dry matter digestibility, 12 hours after feed removal was obtained. PSDM in omasal digesta 24 hours after feed removal was also highly correlated with DMD and energy digestibility (r = 0.97, 0.91, respectively). Very high correlations were obtained between PSDM in abomasal digesta 24 hours after feed removal and digestibility of cellulose, NDF and ADF (r = 0.99, 0.97 and 0.97 respectively). The proportion of particles less than 1mm to the total particles (PIP) in the reticulo-rumen gave the most consistent correlations with intake of dry matter and energy. Voluntary intake of dry matter by the animals on the alfalfa-based diets were significantly higher (P< 0.05) than those on the second-cut Altai wild ryegrass-based diets. However, the apparent digestibility coefficients of the proximate fractions in the Altai wild ryegrass diets were significantly higher (P< 0.05) than those of diets containing alfalfa. Daily intake of digestible energy by animals on 100 % alfalfa was not significantly different from that of animals on 100 % second-cut Altai wild ryegrass. The difference between their respective combinations with tall wheatgrass and Altai wild ryegrass straws were also not significant. It was concluded that PIP and PSDM are indeces based on biologically significant fractions and may therefore have greater relevance than purely mathematical or statistical descriptions of particle size distribution in digesta. In this regard, the relationship between PSDM and digestibility and, PIP and intake are consistent with published theory and can be used in mathematical models to examine control processes in feed intake, rate of passage and digestion. The study also indicated that second-cut Altai wild ryegrass harvested at the prebloom stage can be used as a substitute for alfalfa in an all-forage diet for winter feeding of sheep.
Land and Food Systems, Faculty of
Graduate

Carbohydrates have variable digestibilities and metabolizable energy values in carnivorous fish. Simple sugars are generally more digestible than complex polysaccharides, and low levels of dietary carbohydrate may contribute more metabolizable energy than high levels. Two experiments were conducted to study the effects of dietary level and processing treatment of wheat starch on the digestibility of diets fed to sablefish (Anoplopoma fimbria), in different regions of the digestive tract. Moreover, an experiment was undertaken to determine if the dietary concentration of an indigestible external marker (chromic oxide) influenced its motility, relative to other ingredients in the ingesta, as it passed through the digestive tract. Lastly, a growth experiment was undertaken to compare the performance of sablefish fed formulated diets containing one of two levels of carbohydrate to that of fish fed a natural fish diet. The gastric evacuation of a formulated and a natural diet were also investigated. Apparent digestibility values for the nutrients in a formulated diet (containing 44.4% cooked wheat and 0.1% chromic oxide) fed to sablefish were noted to increase progressively from the anterior to the posterior regions of the intestinal tract. Within each region of the gut, the apparent digestibility values for most nutrients declined over three sample periods. Carbohydrate (nitrogen-free extract) digestibility down to the distal section of the intestine ranged from 51.0 to 82.8%. An experiment designed to assess the effect of carbohydrate treatment on the digestibility of four isonitrogenous, isocaloric diets met with partial failure. It was determined that the 1.0% chromic oxide marker flowed at a differential rate to the rest of the ingesta in the digestive tract, which violated the criteria for an effective marker. Consequently, diet digestibility was not determined in this experiment. Hepatic glycogen levels in fish receiving the dietary treatments were compared, and these values were used to estimate the relative availability (digestibility) of carbohydrate from the respective diets. According to this index, the sequence for digestibility was as follows: pregelatinized starch > cooked wheat > pregelatinized starch/cooked wheat > unprocessed wheat. Differential movement of chromic oxide relative to other ingesta was observed in sablefish fed on alternate days regardless of the dietary concentration of the indigestible marker (0.1 or 1.0%). It was surmised that the feeding protocol established the circumstances from which marker 'streaming' was observed in the results. Differential transport of Cr₂O₃ through the gut by ingested seawater was suggested as a possible mechanism for the phenomenon. Sablefish fed a natural fish diet had the highest growth rates, condition factors, liver lipid levels and the lowest feed conversion ratios and liver glycogen levels. Sablefish fed a diet containing 22.2% cooked wheat had a higher growth rate, condition factor, and a lower food conversion ratio, than those fed a diet containing 44.4% cooked wheat. Ingestion of the 44.4% cooked wheat diet resulted in the highest values for liver glycogen and hepatosomatic index. It was concluded that sablefish have a limited ability to metabolically utilize digestible carbohydrate and that most of the dietary non-protein energy should originate from high quality lipid for maximum protein sparing.
Science, Faculty of
Resources, Environment and Sustainability (IRES), Institute for
Graduate

Radar systems are well known since the end of world war II and are widespread. The basic concept of radar is relatively simple: the system uses the propagation characteristics of electromagnetic waves and works by radiating electromagnetic energy in the space and detecting the echo reflected by the objects (named “target”). The information related to the target is available in the echo signal: the range, or distance, to the target is found from the time it takes for the radiated energy to travel to the target and back; the angular location is detected using narrow beam width directive antennas (i.e. reflector antennas). The ability to discern about the nature and size of the target depends on the radar resolution which is related to the bandwidth and to the electrical size of the antenna. The physical principles of radar are suitable also to the weather radars, used to detect the precipitations at long distance, where the "object of interest” (the target) are the particles of rain and clouds. The detection of these objects involves radar operating at multiple frequencies located in S and C bands, where the wavelength (from 15 to 3.75 centimeters) is comparable to the size of hydrometeors. Radar systems use directive antennas, such as mechanically steered parabolic reflector antennas and planar phased arrays. Aim of these antennas is to concentrate the energy in a narrow beam width of about 1° or 2°. This characteristic not only concentrates the energy on the target itself, but also permits a measure of its direction. In this work we have studied the substitution of reflector horn feeds with printed log-periodic planar feeds in order to obtain the same performance of the horn antennas, but with considerable advantages in terms of weight and cost. The design of log-periodic feeds has been focused on the feed antenna network, and their possible improvements with respect to the state-of-the-art. In the first chapter, a general description of radar systems is given, introducing the Probert-Jones equation for meteorological target. The second and third chapter provide a brief description of antennas concepts and an introduction to reflector antennas. The chapter four is fully dedicated to reflector horn antennas and printed microstrip feed with a brief description of the state-of-art. Finally, in chapter five, three printed log-periodic feed for reflector antennas are presented. The first structure is a printed log-periodic array (LPDA) operating over the C, X and Ku bands. The antenna feeding structure consist of two coaxial cables, in order to realize an infinite balun which provides the required broadband input matching. The second coaxial cable mirrors the first one, connected to the antenna input, and is capable of both stabilizing the antenna phase center and improving the radiation pattern. Both the simulated and measured results have show that the LPDA can be successfully user as a wide band feed for reflector antennas. The second feed consists of a LPDA operating between 3 and 6 GHz, and fed with a coplanar waveguide. The structure has been designed starting from Carrel’s theory, optimized using CST MICROWAVE STUDIO 2012 and then realized. The comparison between simulated and measured results shows that the proposed antenna can be used as feed for reflector broadband applications in the whole operating frequency band, with a very good input matching and a satisfactory endfire radiation pattern. The results obtained with these two printed LPDA provided the starting point for the design of a high gain “V-shaped” log-periodic feed for weather radar applications, operating in S and C band and fed by the dual coaxial cable configuration. The developed feed provides very good input matching and a symmetric radiation pattern both in E-plane and H-plane, with a reasonable gain over the whole operating bandwidth. This feed may be recommended for usage in weather radar systems having a transmitting power less than 400 KW, allowing a discrete operational range.

Thesis (MSc)--Stellenbosch University, 2001.
ENGLISH ABSTRACT: The use of fungal enzymes as ruminant feed digestibility enhancers was investigated. Currently, ruminants may not digest 38 to 80 % of fibrous forages' content. A renewed interest in the potential of feed enzymes for ruminants was prompted by the high costs of livestock production, together with the availability of newer enzyme preparations. Direct application of enzyme preparations can improve in vitro dry matter (DM) and neutral detergent fibre (NDF) degradation, indicating that direct-fed fibrolytic enzymes may be effective in enhancing in vivo digestion of forages. Two commercial enzyme products, Fibrozyme and Celluclast, and fungal extracellular enzyme extracts from Aureobasidium pullulans, Trichoderma reesei, Aspergillus aculeatus, and Thermomyces lanuginosus were evaluated for enhancing in vitro feed digestibility. Fibrozyme addition to both wheat straw and lucerne hay did not improve their in vitro digestibilities, even after a two hour pre-incubation period. The four fungal enzyme extracts did not enhance wheat straw's digestibility, but marginal increases were evident for lucerne hay. Celluclast addition resulted in marginal increases in the digestibility of both oat hay and oat silage, with no enhanced effect on lucerne hay and NaOH-treated wheat straw. No relationship could be found between the level of enzyme activity and the degree of feed digestion in the in vitro assay. Enzyme hydrolysis with Celluclast, in the absence of rumen fluid, gave more conclusive results. All the feed samples tested showed a positive response to Celluclast addition, even the less digestible feeds, namely sugarcane bagasse and wheat straw. In vitro results show that the assays were unsuccessful, because almost all of the experiments conducted showed inconclusive results. Alternative feed evaluation assays, which include the in vivo, in sacco and in situ methods of analysis, as well as gas production measurement and in vitro analysis with the DAISyII system, should be evaluated. A more detailed study of feed digestibility should be motivated by determining which feeds are hydrolysable, their chemical composition, i.e. how accessible the feeds are, and also evaluation of feed mixtures. The enzyme supplements also need to be evaluated for optimum temperature and pH, as well as the compilation of enzyme cocktails.
AFRIKAANSE OPSOMMING: Die gebruik van swamensieme om die verteerbaarheid van herkouervoere te verhoog, is ondersoek. Tussen 38 en 80 % van veselagtige voere se inhoud is tans onverteerbaar. 'n Hernieude belangstelling in die potensiaal van voerensieme vir herkouers word deur die hoë koste van veeproduksie, asook die beskikbaarheid van nuwe ensiempreparate gedryf Direkte byvoeging van ensiempreparate kan die in vitro droëmateriaal (DM) en neutrale onoplosbare vesel (NOV) vertering verbeter, wat daarop dui dat fibrolitiese ensieme wat direk gevoer word, effektief mag wees tydens die in vivo vertering van voer. Twee kommersiële ensiemprodukte, Fibrozyme en Celluclast, en die vier ekstrasellulêre ensieme van vier swamme, naamlik Aureobasidium pullulans, Trichoderma reesei, Aspergillus aculeatus, en Thermomyces lanuginosus is vir hul vermoë om die in vitro verteerbaarheid van voere te verbeter getoets. Byvoeging van Fibrozyme by beide koringstrooi en lusernhooi het geen verbetering in hulonderskeie in vitro verteerbaarheid tot gevolg gehad nie, selfs nie eens na 'n twee uur vooraf inkubasieperiode nie. Koringstrooi se verteerbaarheid is nie verbeter deur die byvoeging van die vier swam-ensiempreparate nie, maar 'n minimale verbetering is wel waargeneem in die verteerbaarheid van lusernhooi. Byvoeging van Celluclast het 'n minimale verbetering in beide hawerhooi en hawerkuilvoer se verteerbaarheid tot gevolg gehad, maar geen effek op lusernhooi of NaOH-behandelde koringstrooi se verteerbaarheid nie. Geen verwantskap is tussen die vlak van ensiemaktiwiteit en die mate van vertering tydens die in vitro toets gevind nie. Ensiematiese afbraak met Celluclast, in die afwesigheid van rumenvloeistof, het meer konkrete resultate gelewer. Al die voermonsters het 'n positiewe respons op die byvoeging van Celluclast getoon, selfs ook die minder verteerbare voere, nl. suikerrietbagasse en koringstrooi. In die wyer konteks was die resulate van die in vitro verteringstoetse egter onbeduidend as gevolg van groot variasie in die metings. Alternatiewe voerontledingstoetse, wat moontlik beter resultate mag lewer, sluit in in vivo, in sacco en in situ analises, asook die meting van gasproduksie en in vitro analise met die DAISyII sisteem. 'n Meer uitgebreide studie van voerverteerbaarheid wat die bepaling van die afbraak van voere, hul chemiese samestelling, met ander woorde toeganklikheid van voere, en die ondersoek van voermengsels behels, behoort aandag te geniet. Die ensiemmengsels behoort ook ten opsigte van samestelling, optimum temperatuur en pH ondersoek teword.

Research was conducted in Sri Lanka to evaluate the feasibility of developing cassava (Manihot esculenta Crantz) leaf meal as an animal feed. In feeding trials with broilers, improvements in performance were observed at 10% inclusion of cassava leaf meal (CLM). High levels (20 and 30%) of CLM depressed gain, feed intake and feed per gain. Weights of spleen and liver (% of body weight) linearly increased with increasing levels of CLM. Carcass pigmentation values favored the CLM-based diets. Dietary additives (methionine, sodium thiosulfate or soybean oil plus methionine) improved the growth of broilers fed 20% CLM diet without, however, having any beneficial effect when added to the basal diet. Gain of broilers tended to decrease with increasing dietary levels of cyanide. Feeding trials with growing pigs showed that CLM can be included up to 26.7% level without any effect on performance. Gain and feed per gain were improved at 13.3% CLM level, whereas marked depressions were noted at 40% CLM level. Results of the balance trials indicated that cassava leaf protein is utilized more efficiently by the pigs, although the nutrients in CLM are not as digestible as those in coconut oil meal. The overall results suggest that bulkiness, low energy content, methionine deficiency and presence of anti-nutritional factors, are the major factors limiting the high level use of CLM in non-ruminant diets. Studies on the processing of CLM revealed that simple drying is sufficient to eliminate almost 90% of the initial cyanide level in the fresh cassava leaves. A combination of chopping and 3-day wilting prior to drying proved most effective in lowering the cyanide level of CLM. Field trials conducted with a short-age cassava variety, MU 22, demonstrated that it is possible to increase cassava leaf dry matter yields by defoliating once during the growing season and to produce within 86% of the normal yield of roots. Two defoliations during the growing season depressed the root crop by more than half.
Ph. D.

Les dues principals contribucions d'aquesta tesis son:
1. una comparació entre els dos instruments per a la promoció de l'electricitat renovable, és a dir, feed-in laws I quotes.
2. una proposta per a l'harmonització de feed-in laws a la Unió europea
La tesis està estructurada en cinc parts.
La Part I explica el sector elèctric liberalitzat, així com les tecnologies existents per electricitat renovable. D'aquestes tecnologies, les que tenen ritmes de creixement majors Durant la última dècada son la solar fotovoltaica i l'energia eòlica. La Part I també explica els principals atributs i impactes de les energies renovables.
La Part II descriu els sistemes, polítiques, mesures i estratègies de finançament per a la promoció de l'electricitat renovable. Els dos instruments més importants són les quotes i els feed-in laws, també coneguts com a tarifes. En un sistema de quotes, s'estableix un objectiu (la quota) d'energies renovable, i es crea un mercat per certificats d'electricitat renovable, de manera que s'aconsegueixi l'objectiu establer d'una manera eficient. En un sistema de tarifes, es garanteix als generadors d'electricitat renovable la compra de tota la seva producció a un preu mínim.
A part de quotes i tarifes, la tesis descriu altres mecanismes i polítiques, tals com sistemes de subhasta, mercats voluntaris, exempcions fiscals, fons d'energia neta, comptadors reversibles, subsidis, i inversió pública en recerca i desenvolupament.. La Part II també considera aspectes tals com accés a la xarxa, definicions i estàndards tècnics, assumptes administratius, establiment d'objectius, educació i conscienciació pública, estratègies de finançament, i gestió de risc.
La Part III descriu estudis de cas. Aquesta tesis no pretén ser un compendi estadístic de totes les polítiques existents a tots els països: Per això uns quants països de la Unió Europea es fan servir com a estudi de cas. La selecció de països s'ha fet pels següents motius: Alemanya i Espanya perquè il·lustren casos exitosos de polítiques de tarifes i primes; Dinamarca perquè es un dels països pioners en el desenvolupament de l'energia eòlica i els sistemes de tarifes que il·lustra els efectes negatius dels canvis de política; França per que il·lustra un sistema hostil a les energies renovables; els Països Baixos com un exemple de multiplicitat de polítiques; Irlanda perquè és un exemple de sistemes de subhasta; Suècia com un exemple de mercats voluntaris i sistemes fiscals verds; i el Regne Unit com un exemple de quotes. també es descriu els Estats Units d'Amèrica, així com el context de la Unió europea, i en particular respecte a la Directiva 2001/77/CE per a la promoció d'electricitat renovable.
La Part IV compara sistemes de quotes i tarifes en aspectes tals com l'eficiència, l'efectivitat, els incentius per a la innovació, l'eficiència sota incertesa, assumptes administratius, riscs regulatoris, finançament, discriminació tecnològica i distribució territorial. La Part IV conclou que les tarifes són instruments superiors a les quotes.
La Part V proposa i elabora polítiques per a l'harmonització dels sistemes de tarifes a la Unió Europea. En concret, proposa una metodologia per a l'harmonització basada en un sistema de primes, amb una prima modular i transparent per als productors d'electricitat renovable. Aquesta prima consideraria els costs tecnològics, els serveis a la xarxa, incentius polítics, i prioritats nacionals. L'enfoc que es proposa inclou mecanismes de flexibilitat per actualitzar les primes, per evitar beneficis inesperats, i per repartir els beneficis de la innovació tecnològica entre els productors i els consumidors, tot i mantenint els incentius per a la innovació. Els mecanismes de flexibilitat inclouen un mecanisme automàtic de revisió d'objectius, un sistema de revisió de primes i un llindar de rendibilitat. Les propostes de la Part V estan basades en la revisió dels principals aspectes de les lleis Alemanyes i Espanyoles.
The two main contributions of this dissertation are:
1. a comparison between two types of policy instruments for the promotion of renewable electricity, namely quotas and feed-in laws; and
2. a proposal for harmonization of feed-in laws in the European Union.
This dissertation is structured in five parts.
Part I explains the deregulated electricity sector and the existing renewable electricity technologies. Among these technologies, the ones with the highest growth rates in the last decade are solar photovoltaic and wind power. Part I also explains the main attributes and impacts of renewable electricity technologies.
Part II describes the existing support schemes, policies, measures and financing strategies for the promotion of renewable electricity. The two most important policy instruments are quotas and feed-in laws. Under a quota system, a target (the quota) is mandated for renewable electricity, and a market for renewable electricity certificates is created, to achieve the established target in a cost-efficient way. Under a feed-in law scheme, renewable electricity generators are guaranteed that all their renewable electricity will be bought at a minimum price.
Besides quotas and feed-in laws, other schemes and policies are described, such as tendering systems, voluntary markets, tax credits, clean energy funds, net metering, subsidies, and public research and development. Part II also addresses aspects such as grid access, definitions and standards, administrative issues, target setting, awareness and education, financing strategies, and risk management.
Part III describes country case studies. Because this dissertation does not pretend to be a compendium of data or existing policies in all countries, a few countries in the European Union have been selected. The selection of countries was broadly made for the following reasons: Germany and Spain because they illustrate successful feed-in systems; Denmark because it is also one of the pioneers of wind power and feed-in laws and illustrates the negative effects of policy changes; France because it illustrates a system hostile to renewables; the Netherlands because it is an example of multiplicity of policies; Ireland because it is an example of tendering systems; Sweden as an example of voluntary markets and green taxes; and the United Kingdom as an example of quotas. The United States is also described, as well as the context of the European Union, particularly with regards to Directive 2001/77/EC on the promotion of renewable electricity.
Part IV provides a comparison between feed-in-laws and quota systems in respect of efficiency, effectiveness, induced innovation, efficiency under uncertainty, administrative issues, regulatory risk, funding, discrimination among technologies and geographical dispersion. Part IV concludes that feed-in laws are superior policy instruments with regards to all those aspects, in some cases based on theory and in some on empirical evidence.
Part V elaborates policy proposals for the harmonization of feed-in laws in the European Union. In particular, it proposes a methodology for harmonization based on a feed-in law with a modular and transparent premium for renewable electricity producers. This premium considers technology costs, some grid services, political incentives and national priorities. The proposed approach includes flexibility mechanisms to update and revise premiums, to avoid windfall profits for producers, and to share technology innovation benefits with electricity consumers while maintaining incentives for innovation. The flexibility mechanisms include a profitability threshold, an automated premium revision, and a target revision trigger. The proposals on Part V are based on the review of the main features of the German and Spanish feed-in laws. Other considerations necessary for harmonization and not described elsewhere in the dissertation are also taken into account in Part V, such as ownership of rights derived from renewables, and exceptions for small non-commercial producers and energy¬intensive industries.

Food waste accounts for about 1/3 of the municipal waste generated in Hong Kong. Using food waste as major ingredients to produce fish feed pellets could ease part of the disposal pressure on the existing landfill sites. The present study focused on the use of food wastes and feed supplements (prebiotic fibres and Chinese herbs) for rearing freshwater fish (grass carp, bighead, mud carp and Nile tilapia) in Hong Kong. Two isonitrogenous formulations, Food Waste Diet A (FWA), consisted of 53% cereal, 10% fruit and vegetables, 8% bone meal, 4% other food waste, 10% fishmeal, 15% corn meal and Food Waste Diet B (FWB), consisted of 25% meat, 28% cereal, 10% fruit and vegetables, 8% bone meal, 4% other food waste, 10% fishmeal, 15% corn meal were manufactured by Kowloon Biotechnology Ltd, were used as feeds for rearing grass carp, bighead, mud carp and Nile tilapia. The essential amino acid profiles and proximate compositions (crude protein, crude lipid and total phosphorous) of the two food waste based feed pellets were compared with other common feed items, including Napier grass, rice bran, breads, noodles, soybean dreg (remains of soybean after juicing for soybean milk) and the commercial feed pellets (Jiefeng® 613). Jiefeng® 613, FWA and FWB possessed 5.83%, 5.76% 5.79% (% protein) of lysine, which could satisfy the dietary requirements of both grass carp and Nile tilapia. Results indicated all the fish feed pellets possessed sufficient essential amino acids and suitable proximate compositions (crude lipid, crude protein, crude fibre and non-fibrous carbohydrate) for both grass carp and Nile tilapia. A field trial was conducted using the three feed pellets (Jiefeng® 613, FWA and FWB) to study their effects on fish growth (grass carp, bighead and mud carp) as well as water quality. FWA that possessing a higher P content (2770 μg/g feed, while control= 967 μg/g feed and FWB= 1942 μg/g feed) favoured the growth of plankton and led to better growth of bighead carp (in terms of length gain, wet weight gain and productivity), while grass carp fed with FWB showed significant better growth (in terms of length gain, wet weight gain, productivity, feed conversion ratio, specific growth rate and protein efficiency ratio), probably due to the relatively lower amount of carbohydrate (24.2%) and CHO:L ratio (1.83) than Control and FWA. Mud carp grew equally well in ponds fed with the three diets. FWB was subsequentially selected for further feeding experiments. A laboratory feeding trial was conducted to study the effects of feeding grass carp and Nile tilapia with FWB on their growth performance in terms of relative weight gain (RWG), feed conversion ratio (FCR), specific growth rate (SGR) and protein efficiency ratio (PER), and protein digestibility. Both fish fed with FWB showed similar growth performances to groups fed with control diet (Jiefeng® 613), while grass carp showed impaired protein digestibility when compared to group fed with control diet. FWB supplemented with 0.3% of vitamin-mineral premix (VMP) significantly improved the growth performance of both fish species and protein digestibility for grass carp. Results suggested that FWB incorporation with VMP would be necessary as it significantly enhanced growth of the fish. Four dietary supplements (inulin, mannan-oligosacharride, huangqi and goji, at the rates of 0.2% or 2%, w/w) were incorporated into FWB for further enhancing fish growth as well as non-specific immunity of grass carp and Nile tilapia. Grass carp fed with 0.2% and 2% inulin, 2% MOS and 0.2% goji, and Nile tilapia fed with 0.2% goji had significantly enhanced growth (RWG, FCR, SGR and PER). Both prebiotic fibres and Chinese herbs boosted the tested non-specific immune parameters (total serum immunoglobin, serum bactericidal activity and anti-protease activity) of both species. Among all the dietary supplements, 0.2% goji appeared to be the best supplement for both grass carp and Nile tilapia as it significantly enhanced the growth among all experimental diets. Grass carp and Nile tilapia fed with 0.2% showed about 10% and 30% higher RWG, 10% and 30% lower FCR value, respectively, than groups fed with other experimental diets. Moreover, all the tested non-specific immune parameters (total serum immunoglobin, serum bactericidal activity and anti-protease activity) were significantly enhanced when compared with the groups fed with control diets (Control and FWB without supplementation) . The present study demonstrated the feasibilities of using food wastes incorporated with feed supplements (prebiotic fibres and Chinese herbs) to enhance fish growth and immunity, for the sustainable development of Hong Kong inland aquaculture.

Effects of tallow supplementation on dietary nutrient and minimal amino acid utilization in the laying hen were studied in two experiments. In the first experiment diets contained six levels of animal tallow ranging from 0 to 10%. Percent egg production and egg mass were not significantly affected by tallow. Body weight was significantly increased by 2% tallow was maximum at 6%. Addition of up to 6% fat improved feed conversion without adversely affecting other production characteristics. Metabolizable energy (ME) intake increased from 305.1 to 322.4 kcal/hen/d over the range of 0 to 6% tallow with no further improvement at higher tallow levels. Maximum net energetic efficiency was obtained with 2 and 4% tallow. Ability to digest tallow declined significantly with hen age. Higher tallow ME values were obtained from calorimetry data than from digestibility measurements due to beneficial effects of tallow on digestibilities of fat and protein in the basal diet. No improvement in starch retention was observed with tallow supplementation. In the second experiment, diets containing four levels of protein (15.0, 13.6, 15.0 + methionine and 17.0%) without and with 3% tallow were fed to hens housed in an open cage house or an insulated, evaporatively cooled house. Egg production and egg mass were significantly higher in the insulated house. This study indicates that reducing total protein below the National Research Council (NRC, 1984) recommended level significantly reduced egg production by birds housed in an open house. Supplemental methionine to provide .60% TSAA was required for maximum egg production. Egg production was significantly improved with the low protein diet when 3% tallow was added; however, egg production rate supported by this combination was significantly below that obtained with the 17% protein diet either with or without added tallow. For birds housed in the insulated, evaporatively cooled house the diet based on the NRC amino acid recommendations appeared to be optimal for performance, even with a lower protein level. No additional benefits were obtained in egg production with 3% tallow in any of the diets under these housing conditions.

The use of shrimp processing waste with other cheap raw materials such as cassava was studied as a potential low cost animal feed, specially in developing countries. The impact on the economies of the shrimp industry and possible effects on the environmental were taken into consideration in developing the project.

Feeds werden unter anderem eingesetzt, um Nutzer in einem einheitlichen Format und in aggregierter Form über Aktualisierungen oder neue Beiträge auf Webseiten zu informieren. Da bei Feeds in der Regel keine Benachrichtigungsfunktionalitäten angeboten werden, müssen Interessenten Feeds regelmäßig auf Aktualisierungen überprüfen. Die Betrachtung entsprechender Techniken bildet den Kern der Arbeit. Die in den verwandten Domänen Web Crawling und Web Caching eingesetzten Algorithmen zur Vorhersage der Zeitpunkte von Aktualisierungen werden aufgearbeitet und an die spezifischen Anforderungen der Domäne Feeds angepasst. Anschließend wird ein selbst entwickelter Algorithmus vorgestellt, der bereits ohne den Einsatz spezieller Konfigurationsparameter und ohne Trainingsphase im Durchschnitt bessere Vorhersagen trifft, als die übrigen betrachteten Algorithmen. Auf Basis der Analyse verschiedener Metriken zur Beurteilung der Qualität von Vorhersagen erfolgt die Definition eines zusammenfassenden Gütemaßes, welches den Vergleich von Algorithmen anhand eines einzigen Wertes ermöglicht. Darüber hinaus werden abfragespezifische Attribute der Feed-Formate untersucht und es wird empirisch gezeigt, dass die auf der partiellen Historie der Feeds basierende Vorhersage von Änderungen bereits bessere Ergebnisse erzielt, als die Einbeziehung der von den Diensteanbietern bereitgestellten Werte in die Berechnung ermöglicht. Die empirischen Evaluationen erfolgen anhand eines breitgefächerten, realen Feed-Datensatzes, welcher der wissenschaftlichen Gemeinschaft frei zur Verfügung gestellt wird, um den Vergleich mit neuen Algorithmen zu erleichtern.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O problema que justifica o presente estudo refere-se à falta de semântica nos mecanismos de busca na Web. Para este problema, o consórcio W3 vem desenvolvendo tecnologias que visam construir uma Web Semântica. Entre estas tecnologias, estão as ontologias de domínio. Neste sentido, o objetivo geral desta dissertação é discutir as possibilidades de se imprimir semântica às buscas nos agregadores de notícia da Web. O objetivo específico é apresentar uma aplicação que usa uma classificação semi-automática de notícias, reunindo, para tanto, as tecnologias de busca da área de recuperação de informação com as ontologias de domínio. O sistema proposto é uma aplicação para a Web capaz de buscar notícias sobre um domínio específico em portais de informação. Ela utiliza a API do Google Maps V1 para a localização georreferenciada da notícia, sempre que esta informação estiver disponível. Para mostrar a viabilidade da proposta, foi desenvolvido um exemplo apoiado em uma ontologia para o domínio de chuvas e suas consequências. Os resultados obtidos por este novo Feed de base ontológica são alocados em um banco de dados e disponibilizados para consulta via Web. A expectativa é que o Feed proposto seja mais relevante em seus resultados do que um Feed comum. Os resultados obtidos com a união de tecnologias patrocinadas pelo consórcio W3 (XML, RSS e ontologia) e ferramentas de busca em página Web foram satisfatórios para o propósito pretendido. As ontologias mostram-se como ferramentas de usos múltiplos, e seu valor de análise em buscas na Web pode ser ampliado com aplicações computacionais adequadas para cada caso. Como no exemplo apresentado nesta dissertação, à palavra chuva agregaram-se outros conceitos, que estavam presentes nos desdobramentos ocasionados por ela. Isto realçou a ligação do evento chuva com as consequências que ela provoca - ação que só foi possível executar através de um recorte do conhecimento formal envolvido.
The problem addressed in this work refers to the lack of semantics in Web search engine. As solution, the W3 consortium has been developing technologies that aim to build a Semantic Web, including the domain ontology. Considering this issue, the work main goal is to discuss the possibilities of placing semantics context in the searches in Web feed applications. The specific goal is to propose a Web application that uses a semi-automatic classification of news, by joining information retrieval technologies and domain ontology. The software is able to get news about a given domain from Web information portals. It uses the Google Map API VI for gather the new geo-referenced location, whenever this information is available. To show the proposal feasibility, an example was developed supported by an ontology in the domain of rainfall and its consequences. The results of this new ontology-based feed are allocated in a database e make available for query via the Web. It is expected that the proposed feed offers more relevant results than the current feeds. In addition, the union of technologies sponsored by the W3C and traditional search methods on Web pages were satisfactory for the intended purposes. Ontology is showed as multi-use tool and its value in Web search can be extended for appropriate computer applications. In the example presented, other concepts were added to the word rainfall, which is present in the deployments caused by it. This highlighted the connection of the event rainfall with its consequences, action that was only possible to run through a cutout of the formal knowledge involved.

The most common disease causing elements in feed is of microbial nature. Therefore it is of great importance for horse owners to be familiar with the fundamental requirements for microbial growth in feeds and the problems that can originate in case of insufficient handling. However, horse owners are not organized in a way that makes it easy to reach them with information as a target group. Additionally, most horse owners only have one horse and limited possibilities for education in feed safety. Thus, there is need for an easy accessed education material that is explicitly directed towards horse owners. The fundamental content of such an education material was composed in this project. Focus was on the importance of good microbial quality in horse feed and the material was structured into three chapters; FEED SAFETY, MICROORGANISMS IN FEEDS and CONSERVATION, STORING AND FEEDING. The aim was to publish the material as part of a larger web based education package on the web page, http://www.sva.se of the Swedish National Veterinary Institute. The basic structure for such a web education was also composed in this project.

Includes bibliographical references (leaves 290-309) Investigates aspects of the intake and utilization of barley grain and grain legume supplements by sheep fed low quality pasture hay and when grazing mature summer pastures.

Two experiments determined the effects of flaxseed supplementation on reproductive parameters in sheep. In experiment one, 240 multiparous Rambouillet ewes were assigned to one of two treatments: basal ration alone or basal ration with a Flaxlic® Sheep Tub offered over 35 days. Serum was collected weekly for progesterone (P4). Flaxseed supplementation did not improve progesterone concentration or reproductive parameters (P ≥ 0.26). In experiment two, 120 Rambouillet ram lambs were assigned to one of two treatments: basal ration alone or basal ration with a Flaxlic® Sheep Tub offered over 112 days. Scrotal circumference measurements, serum for testosterone, and semen were collected on day 84 and 112. Day effects were found for select semen measurements, testosterone, weight, and scrotal circumference (P ≤ 0.05). There was no effect of treatment on testosterone concentration (P = 0.99) or any semen quality characteristics (P ≥ 0.33). Overall, tub supplementation did not alter reproductive ability.

Web feeds are a popular technique to distribute information about contents of web pages. RSS and Atom are two standards used to syndicate web contents as web feeds. This project investigates how to make different kinds of Internet web feeds searchable by implementing a general wrapper for web feeds in an extensible and functional DBMS, Amos II. The system, RSS-Amos, makes it possible to search the contents of any RSS or Atom based web feed using the query language AmosQL. New web feeds simply have to be declared to the system in order to make them searchable. The system guarantees that added feeds always are up to date when queries are made. The wrapper is implemented in Java using the ROME API from java.net. The project includes an evaluation of the performance of the system. Due to the fact that the actual data sources are located on the Internet, a cache of read feeds has been implemented to improve performance. The cache makes queries over 150 times faster.

Assignment (MPhil)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: The aim of this study was to evaluate the performance and profitability of different dietary specifications for broiler chickens slaughtered at 35 days of age. Two trials were performed to evaluate different production parameters. The results of these trials were compared to the predicted results of the EFG broiler model. No carcass data were available for the two trials mentioned above. Therefore, in order to evaluate the accuracy of the broiler model when predicting carcass characteristics, two published data sets (Leeson et al., 1996a) were used. Predicted and actual values were compared, evaluated and discussed. Two broiler trials were performed. In Trial One the amino acid density decreased throughout the range of three treatments from prestarter to finisher diets. In Trial Two the amino acid density decreased only in the four finisher diets. The main difference between predicted and actual results was the response to body weight. The model predicted a steady increase in feed intake to compensate for the lower dietary specifications while body weight did not change significantly. This increase in feed intake seems to be enough to maintain body weight. Trial birds also increased their feed intake as dietary amino acid density decreased, but this compensation seemed to be too low to maintain body weight compared to the control diet. The birds may find it easier to compensate when they have time to adapt to the specification. There is evidence in the literature that birds need seven days to adapt their feed intake to a lower feed specification (Leeson et al., 1996a). It can be speculated that the trial birds started to loose body weight due to a lower amino acid intake in this period. The model seems to adapt feed intake immediately after a change in diet specification. The simulation on literature data lead to the following conclusions: 1) Broilers posses the capacity to increase their feed intake with at least 65% should finisher diets with lower amino acid and energy concentrations be supplied. If only the energy concentration of finisher diets were decreased, the increase in feed intake will be around 30%. (see Table 16 and 23) 2) The accurate prediction of feed intake from the given dietary specification has a major influence on the accuracy of the prediction of broiler performance. 3) Amino acid density and DLys:ME ratio plays a significant role in the control and prediction of feed intake. The EFG broiler model is based on sound scientific principles. The model is comprehensive and can be used for a wide range of environmental and management conditions as well as dietary conditions. The nutritionist can use the model with confidence to assist in practical feed formulation. The actual strength of the model lies in the time and money being saved compared to practical trials.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie is om die prestasie en winsgewendheid van braaikuikens te bepaal wanneer voere met verskillende digthede tot op 35 dae gevoer word. Twee eksperimente is uitgevoer om produksieresultate te evalueer. Die resultate van hierdie eksperimente is met die voorspelde waardes uit die EFG simulasie-model vergelyk. Aangesien geen karkasdata vir bogenoemde eksperimente beskikbaar was nie, is twee gepubliseerde datastelle gebruik om hierdie deel van die model te evalueer (Leeson et al., 1996a). Twee braaikuiken eksperimente is uitgevoer. Eksperiment Een het uit drie behandelings bestaan waarvan die aminosuur-konsentrasie vanaf dag een tussen behandelings verskil het. In Eksperiment Twee het die aminosuur-konsentrasie net in die vier afrondingsdiëte verskil. Liggaamsmassa op 35 dae het die grooste verskil tussen voorspelde- en werklike waardes getoon. Beide voorspelde en werklike innames het in albei eksperimente verhoog soos wat aminosuur-konsentrasie afgeneem het. Voorspelde liggaamsmassa het egter konstant gebly terwyl werklike data 'n afname in liggaamsmassa getoon het. Dit bleik dat die voorspelde toename in innames voldoende was om massa te onderhou terwyl die voëls in werklikheid nie genoeg gekompenseer het nie. Leeson et al., 1996a het tot die gevolgtrekking gekom dat braaikuikens minstens sewe dae benodig om hul voeriname by 'n nuwe spesifikasie aan te pas. So 'n stadige aanpassing kan daartoe lei dat energie- en aminosuur-inname daal indien 'n dieet met laer spesifikasie gevoer. Dit sal daartoe lei dat die kuikens liggaamsmassa verloor. Uit die literatuur simulasies is die volgende afleidings gemaak: 1) Braaikuikens besit die vermoeë om voerinname in die afrondingstyd met minstens 65% te verhoog indien 'n afrondingvoer met laer amiosuur- asook energiekonsentrasie gevoer word. Indien net die energiekonsentrasie verlaag word, sal die inname met sowat 30% verhoog. 2) Die akkurate voorspelling van inname is krities vir die akkurate voorspelling van produksieparameters. 3) Aminosuur-digtheid en DLys:ME speel 'n belangrike rol in die beheer en voorspelling van voerinname by braaikuikens. Die EFG braaikuikenmodel is op suiwer wetenskaplike beginsels geskoei. Die model is omvattend en kan vir 'n wye reeks van omgewings- en bestuurstoestande asook dieet-spesifikasies gebruik word. Die voedingkundige kan die model met vertroue gebruik om met praktiese voerformulering by te staan. Die model kan die formuleerder baie tyd spaar aangesien praktiese eksperimente ingeperk kan word.

This research reports on the determination of the effects of fish size and feed pellet size on the settling characteristics of Rainbow trout (Salmo gairdneri) culture, tank cleaning wastes. Flocculant particle settling curves (Type II) were developed from settling column analysis of cleaning wastes from 11-311 gram Rainbow trout fed a moist pellet diet (Oregon Moist Pellet ®). Four feed pellet sizes were investigated: 3/32, 1/8, 5/32 and 3/16 inch. Overall non-filterable residue removal curves and individual particle settling velocity distribution curves, derived from the Type II settling curve of each fish size and feed pellet size group, were compared. Slopes and y-intercepts of the linearized overall non-filterable residue removal curves and individual particle settling velocity distribution curves were compared using the Equality of Slope Test (S:SLTEST). Results of the test for a common regression equation indicated there were no significant differences in the proportional distribution of particle sizes within the cleaning wastes. Variations observed in the initial rates of removal within the overall non-filterable residue removal curves were considered insignificant Settling trials were pooled in order to obtain single curves, characterizing the overall solids removal rate and the individual particle settling velocity distribution of the waste solids.
Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate