• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 806
  • 297
  • 183
  • 55
  • 50
  • 38
  • 36
  • 36
  • 33
  • 29
  • 23
  • 14
  • 14
  • 14
  • 14
  • Tagged with
  • 1894
  • 487
  • 323
  • 251
  • 212
  • 183
  • 181
  • 167
  • 132
  • 121
  • 117
  • 109
  • 107
  • 106
  • 100
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
501

A study to explore the perceptions that South African chiropractors have regarding the perceived role and impact of research within the profession

Gordon, Julani January 2012 (has links)
Dissertation submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2012. / The Chiropractic profession has made significant progress with regard to the production of high quality and clinically relevant research in the last 20 years. This correlates with a spike in development within the chiropractic profession as well as its acceptance by the medical fraternity and public. The responsibility for continuing this positive trend is dependent on the chiropractic graduates and practitioners of the future. Therefore, it is important to establish the current perceptions and utilization of research by Chiropractors, so that future research can be built around the needs and requirements of today’s practitioners, thereby ensuring the profession’s continued development and future in health care. The aim of this study was to determine the perceptions that Chiropractors have of research and its relevance / utilization in practice. Method: The study was a quantitative questionnaire based, self administered survey. The sample group included all Chiropractic practitioners currently practising in South Africa (N=515). Results: There was a response rate of 35% (n=174). The results indicated that the perception of research was very positive overall, with the strongest positive response being that research adds credibility to the profession. However, most respondents disagreed with the statement that chiropractors who had done research had an advantage above those who had not. There was a positive, albeit weak correlation between perceptions and utilization of research, indicating that as perceptions increased, so did utilization of research. The area of greatest concern was that even though a high degree of research utilization was reported by chiropractors, research was least likely to be used to change conditions, policies or practices in practice. v Conclusion: The most significant factors associated with positive perceptions and utilization were found to be publishing in a journal and receiving referrals from other health care practitioners. Chiropractors who indicated an interest in doing research again were also very positively linked to utilization. It would seem that even though chiropractors perceive research positively, their implementation into practice has some hurdles that impede the full integration of research into practice. As very few demographic and personal attributes of the South African chiropractor were found to be primarily responsible for low utilization of research in practice, it can be hypothesised that the factors impeding research implementation are most likely environmental in nature.
502

PULSE SHAPED CONSTANT ENVELOPE 8-PSK MODULATION STUDY

Tao, Jianping 10 1900 (has links)
International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The most bandwidth-efficient communication methods are imperative to cope with the congested frequency bands. Pulse Shaping methods have excellent effects on narrowing bandwidth and increasing band utilization. The position of the baseband filters for the pulse shaping is crucial. Filters after the modulator will have non-constant envelope and before the modulator will have constant envelope. These two types have different effects on narrowing the bandwidth and producing bit errors. The constant envelope 8 PSK is used throughout the simulations and is compared with the non-constant envelope results. This work provides simulation results of spectrum analysis and measure of bit errors produced by pulse shaping in an AWGN channel.
503

Studies on the suitability of Jatropha curcas kernel meal as an alternative protein source in diets for carp (Cyprinus carpio) and tilapia (Oreochromis niloticus)

Krome, Carsten Alexander January 2014 (has links)
Aquaculture production is increasing annualy and wild fisheries for fishmeal production remain stagnant. As a consequence, extensive research has been deployed to reduce dietary fishmeal inclusion in feeds of farmed species. Usage of alternative protein sources derived from plants continues to increase with the most popular sources being oilseeds, legumes and cereal grains. The downside of these sources is that most of them could directly be used for human consumption arising legitimate criticism from voices referring to countries where protein shortages lead to malnutrition among the population. Jatropha curcas is a tropical oilseed with upcoming popularity for sustainable fuel sourcing. The plant is thought to thrive in semi-arid and arid areas, not just producing oil, but at the same time reclaiming previously eroded land for the local population. For these reasons, annual cultivation of Jatropha curcas is thought to rise over the next decades. After oil is extracted from the seed, the remaining press cake, is currently used as a fertilizer or energy source. This is mostly due to toxic phorbol esters that until recent- ly limited any nutritional applications. In 2011, a method to detoxify Jatropha press cake was developed and paved the way for nutritional research on the resulting detoxified Jatropha curcas kernel meal (JKM) to be launched. JKM offers very high protein content with a balanced amino acid composition suggesting opportunities for usage as a feedstuff in aquaculture diets. JKM further has higher mineral content than comparable oilseeds. However, potential anti-nutritional factors (ANFs) present in the meal could lead to impairment of nutrient availability or other adverse effects. Previous research has already started to evaluate JKM as a protein source for a variety of aquaculture species. This thesis attempts to further identify the potential of JKM as a protein source and assess the effects of JKM on the development of two model cultured teleost species, common carp (Cyprinus carpio) and Nile tilapia (Oreochromis niloticus), as they represent two of the most farmed species, particularly in the tropics. The work comprises growth trials on both species using fishmeal as a subject of replacement in solely fishmeal protein-based diets and on more practical fishmeal/plant protein-based diets. It engages with the effects of phytate, a prominent component of JKM with potential anti-nutritional attributes and commercially available phytase feed supplements to diminish these attributes, as well as oxalate, another plant-specific component with high concentrations in JKM and with limited attention in aquaculture nutrition research. Carp and tilapia showed varying results with different inclusion levels of JKM. For carp 50% fishmeal replacement was possible without losses in growth in diets where fishmeal was the only bulk protein source (Chapter 3.1), Tilapia showed slightly worse growth at a 30% replacement level (Chapter 3.2). A steep decline in growth could be observed when replacing 100% fishmeal with JKM in carp (Chapter 3.1), while tilapia showed no difference at that level compared to 30% replacement (Chapter 3.2). In practical diets, 100% of fishmeal could be replaced by JKM without any adverse effects on growth of carp (Chapter 3.3), while tilapia showed a slight, but significant linear negative correlation with higher inclusion levels of JKM (Chapter 3.4). Phytase addition in tilapia feeds was identified as having no obvious impact on growth in JKM based diets where enough available phosphorus was provided through mineral supplementation (Chapter 4.1). In JKM based diets where available phosphate was not added, phytase addition showed a tendency to increase growth and significantly increased mineral retention and decreased phosphorus effluent contamination (Chapter 4.2). Phytase application through pre-incubating JKM along with citric acid exerted a positive effect of growth on carp when fishmeal protein was replaced by 50% (Chapter 3.1). Phytase was further shown to completely hydrolyze phytate in vitro; however, incomplete hydrolysis was observed in vivo in tilapia (Chapter 4.3). Dietary soluble oxalate added to fishmeal based diets for carp showed better growth parameters, nutrient and mineral retention at inclusion levels 1.5% and higher (Chapter 5.1). For tilapia, a trial could demonstrate adverse effects of oxalate on potassium, calcium, manganese and zinc digestibilities, in this case without negative effects on growth (Chapter 5.2). For both, carp and tilapia, an impact of oxalate on lipid metabolism was evident, lowering body lipid content and blood cholesterol in inclusion levels from 1.5% or higher. JKM can become a valuable alternative to present dietary protein sources in aquaculture feeds. The nutritional attributes of JKM need further research, especially longer-term testing in a commercial scenario and application in commercially produced feeds. Results of this thesis pose a useful addition to previous research and can be referred to for realizing these next steps.
504

Health and Health Care Utilization among the Unemployed / Hälsa och vårdutnyttjande bland arbetslösa

Åhs, Annika January 2006 (has links)
The number of persons who are not employed has increased in Sweden since the early 1990s. Unemployment has been found to influence health, especially when unemployment rates are low. The extent to which unemployment affects health when unemployment is high is less clear, and this needs to be further studied. To improve health in the population, the health care system should offer equal access to health care according to need. It is important to study whether the employment status hinders the fulfilment of this goal. This thesis is based on four papers: Paper I and II aimed at analysing self-rated health versus mortality risk in relation to employment status, during one period of low unemployment and one period of high unemployment. Paper III and IV assessed the use of medical health care services and unmet care needs among persons who were unemployed or otherwise not employed. The goal was to analyse what health problems lead people to either seek or abstain from seeking care, and what factors encumber or facilitate this process. The overall results indicate that being unemployed or outside the labour force was associated with an excess risk of poor self-rated health, symptoms of depression, mental and physical exhaustion and mortality. The differences in self-rated health between the unemployed and employed were larger when unemployment levels were high, than when they were low. More groups of the unemployed were also afflicted with poor health when unemployment was high. Thus, poor health among the unemployed seems to be a public health problem during high levels of unemployment. Lack of employment was related to abstaining from seeking care, despite perceiving a need for care, and this was related to psychological symptoms. To deal with the needs of the unemployed and others who are outside the labour force it would be useful to develop and implement interventions within the health care system. These should focus on psychological and psychosocial problems. Future research should analyse how to facilitate health-promoting interventions among persons who are not anchored in the labour market.
505

Model-based data mining methods for identifying patterns in biomedical and health data

Hilton, Ross P. 07 January 2016 (has links)
In this thesis we provide statistical and model-based data mining methods for pattern detection with applications to biomedical and healthcare data sets. In particular, we examine applications in costly acute or chronic disease management. In Chapter II, we consider nuclear magnetic resonance experiments in which we seek to locate and demix smooth, yet highly localized components in a noisy two-dimensional signal. By using wavelet-based methods we are able to separate components from the noisy background, as well as from other neighboring components. In Chapter III, we pilot methods for identifying profiles of patient utilization of the healthcare system from large, highly-sensitive, patient-level data. We combine model-based data mining methods with clustering analysis in order to extract longitudinal utilization profiles. We transform these profiles into simple visual displays that can inform policy decisions and quantify the potential cost savings of interventions that improve adherence to recommended care guidelines. In Chapter IV, we propose new methods integrating survival analysis models and clustering analysis to profile patient-level utilization behaviors while controlling for variations in the population’s demographic and healthcare characteristics and explaining variations in utilization due to different state-based Medicaid programs, as well as access and urbanicity measures.
506

An evaluation of degradable protein and nonprotein nitrogen on intake and digestion by Dohne merino sheep fed wheat straw

Nolte, Joubert van Eeden 12 1900 (has links)
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.
507

Animal performance from natural pastures and the effects of phosphorus supplementation

Read, Marion Victoria Pearl 03 1900 (has links)
Thesis (MScAgric) -- Stellenbosch University, 1984. / INTRODUCTION: This study was initiated by the various reports of improved animal performance resulting from supplementary feeding of grazing ruminants and in this respect, it may be regarded as a feasibility study of the ability of the natural pasture at the applied stocking rates, to supply the animal with its nutrient requirements, since before providing the animal with supplementary nutrients, it is necessary to identify those which may possibly limit animal production. The criti= cal test of such a limiting nutrient would be an improved animal performance, resulting from supplementation of the nutrient suspected as being limiting, under grazing conditions.
508

Comparison of production parameters, gut histology, organ weights, and portion yields of broilers supplemented with Ateli plus

Teuchert, Nicole 04 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Antibiotic growth promoters (AGP’s) have been used in feed of production animals to improve their growth performance and disease resistance. However, there has been an increase in the presence of antibiotic residue in animal products, as well as an increase in untreatable illnesses due to antibiotic resistant bacteria. This led to the European Union banning the use of antibiotic growth promoters, in production animals, in 2006. An alternative to AGP’s is therefore needed in animal feed in order to maintain performance. Plant extracts and essential oils have gained much attention, due to their natural antimicrobial, antibacterial, anticoccidial and antioxidant properties. This study tested the efficiency of Ateli plus®, an oregano plant extract based product, as a replacement to AGP’s on production parameters, carcass characteristics and organ and gut health of broilers. This study consisted of five treatments fed to broilers from hatch till 33 days of age, fed in three phases; starter, grower and finisher. The treatment diets consisted of a negative control (no AGP), positive control (AGP), Ateli plus® at 1kg/ton (Ateli plus® min), Ateli plus® at 2kg/ton for week one followed by 1kg/ton for the remainder of the period (Ateli plus® max), and AGP plus Ateli plus® max (AGP plus Ateli plus® max). Results from this study show that there was no difference in performance parameters between treatments. The performance parameters tested included liveability, average daily gain (ADG), average weekly feed intake, average cumulative feed intake, average weekly live weight, average cumulative weight gains, feed conversion ratio (FCR), cumulative FCR and the European production efficiency factor (EPEF). Broiler breast and thigh muscle pH and colour (L*, a* and b*) reading values were measured, showing a trend for improved L* colour reading value and ultimate pH, in broilers supplemented with Ateli plus®. This leads to an increase in water binding capacity and tenderness, therefore resulting in an improvement in meat quality. No differences were shown for dressing percentage and portion percentages relative to carcass weight. No significant differences were seen for tibia bone Ca and P content, or tibia bone fat, moisture or ash percentages. However a significant decrease in tibia bone strength was found in all broilers supplemented with Ateli plus® diets and the negative control diet, compared to AGP supplemented broilers. Gut morphology showed no consistent effect of treatment on villi height or crypt depth of the duodenum, jejunum and ileum. No significant differences between treatments were found for organ pH or organ weights, except the gizzard, which was heavier for Ateli plus® max supplemented broilers. Ateli plus® shows promise on improving meat quality characteristics of broilers, however the significant decrease in tibia bone strength in Ateli plus® supplemented broilers is a major concern and needs to be researched further. Ateli plus® acts as a good AGP replacement, as broiler performance for the Ateli plus® supplemented broilers was maintained, and not decreased, when compared to the AGP supplemented broilers. However, the broilers fed the negative control diet had performance parameters statistically equal to both the Ateli plus® and AGP supplemented broilers, as well as no significant differences between organ weights were found. It can therefore be said that the broilers were raised under good management, and their optimal environmental conditions. Therefore conclusive effectiveness of Ateli plus® as a replacement for AGP on broiler performance cannot be reported from this study. / AFRIKAANSE OPSOMMING: Antibiotiese groeistimulante (AGP’s) word gereeld as voerbymiddels vir diere gebruik om groei en siekte weerstandbiedenheid te verbeter. Die verbod op die gebruik van antibiotika as 'n groeipromotor in die Europese Unie (sedert 2006) kan toegeskryf word aan die toename in onbehandelbare siektes as gevolg van weerstandbiedende bakterieë, asook die teenwoordigheid van residue in die dierlike produkte. Alternatiewe vir AGP’s in dierevoeding word dus benodig om produksie te handhaaf. Plant ekstrakte en essensiële olies het baie aandag gekry as gevolg van hul natuurlike antimikrobiese, antibakteriële, antikoksidiese en antioksidatiewe eienskappe. 'n Studie is gedoen om die doeltreffendheid van Ateli plus® ('n origanum plant ekstrak gebaseerde produk) op groei produksie parameters, karkaseienskappe, orgaan- en dermgesondheid te bepaal wanneer Ateli plus® as 'n AGP plaasvervanger in die dieëte van braaikuikens gebruik word. Gedurende die proef was vyf verskillende diëte/behandelings vir 33 dae vir braaikuikens gevoer. Die behandelings het bestaan uit 'n negatiewe kontrole (geen AGP), positiewe kontrole (AGP), Ateli plus® teen 1kg/ton (Ateli plus min), Ateli plus® teen 2kg/ton vir die eerste week gevolg deur 1kg/ton vir die res van die tydperk (Ateli plus® max), en AGP plus Ateli plus® max (AGP plus Ateli plus® max). Resultate van hierdie studie toon dat behandelings nie 'n effek op produksie parameters gehad het nie. Die groei produksie parameters wat getoets is sluit in oorlewing, gemiddelde daaglikse toename (GDT), die gemiddelde weeklikse voer-inname, gemiddelde kumulatiewe voerinname, gemiddelde weeklikse lewendige massa, gemiddelde kumulatiewe gewig toename, voeromsetverhouding (VOV) en die Europese produksie doeltreffendheid faktor (EPEF). Die pH en kleur (L*,a* en b* waardes) van die dy- en borsspier is gemeet. Ateli plus® aanvulling in braaikuiken diëte het 'n tendens getoon vir verbeterde L * en finale pH waardes in die spiere, wat lei tot 'n toename in waterhouvermoë en sagtheid en dus verbeterde vleiskwaliteit. Geen verskille tussen behandelings is gevind vir uitslagpersentasie en die massa van porsies (uitgedruk as persentasie relatief tot karkasgewig) nie. Behandelings het nie 'n effek op die vet, vog, as persentasies of Ca- en P-inhoud van die tibia gehad nie. In vergelyking met AGP aangevulde braaikuikens, is 'n beduidende afname in die tibia breeksterkte van kuikens in die negatiwe kontrole groep en kuikens wat met Ateli plus® aangevul is, gevind. Spysverteringskanaal morfologie het getoon dat behandeling geen konsekwente effek op villi hoogte of krip diepte van die duodenum, jejunum en ileum gehad het nie. Slegs die krop massas van kuikens wat met Ateli plus® max aangevul is, was swaarder in vergelyking met hoenders in die ander behandelings; verder is geen beduidende verskille tussen behandelings gevind vir orgaan pH of orgaan gewigte nie.
509

Consumptive wildlife utilization as a land-use form in Namibia

Erb, Karl Peter 03 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: This study summarizes data for the consumptive wildlife industry in Namibia, both in terms of resource availability and current utilization and monetary value. Based on these data a spreadsheet-based cash-flow model is developed to simulate scenarios and to explore what constitutes the critical parameter. Based on this data synthesis and modelling, recommendations are made and conclusions drawn. Chapter one gives an overview of Namibia's economy, with special reference to the livestock and wildlife industry. The fact that the commercial livestock herd has been shrinking over the years is pointed out, as well as the stable output achieved through better management practices. The literature research has shown that wildlife ranching could be a viable alternative to livestock farming as practised in southern Africa, especially in the more arid areas with higher rainfall variability. Chapter two outlines the resource availability, based on the distribution and densities of the more common species. The occurrence of the rarer species is touched on. The point is made that it is very difficult to accurately count wildlife over large areas and that, as elsewhere, Namibia's wildlife at a regional scale is underestimated. Chapter three documents the consumptive use of wildlife. Trophy hunting, the most important segment in terms of national income, is discussed together with the live sale of game, live export of game, venison production and night culling. A comparison is made between the economic outputs of the wildlife industry versus that of the commercial cattle industry. Chapter four covers financial modelling and the economics of the wildlife industry in Namibia. A spread-sheet based deterministic model is developed to explore the cash-flow implications of various game ranching options, such as using different species mixes, owning land of different carrying capacities and offering different services. Chapter five addresses policy and legislative issues in relation to the wildlife industry. Topics such as property rights and exclusive utilization rights, industry representation and the forming of smart partnerships with primary resource users are covered. Broad recommendations are made to the Ministry of Environment and Tourism. Chapter six is used for a concluding synthesis of the previous four chapters. / AFRIKAANSE OPSOMMING: Hierdie studie som die konsumptiewe wildlewe industrie in Namibie op in terme van van beide beskikbaarheid, huidige verbruik en monetere waarde van hierdie hulpbron. Gebaseer op hierdie data is 'n kontantvloei model opgestel om vooruitskouings te simuleer, met betrekking op aanbevelings en gevolgtrekkings. Hoofstuk een gee 'n oorsig van die Namibiese ekonomie met spesiale verwysing na die vee- en wildboerdery. Daar word uitgewys dat die gesamentlike kommersiele veekudde oor die afgelope aantal jare kleiner geword het, terwyl die opbrengs stabiel gebly het deurdat better bestuurspraktyke toegepas is. Die literatuurstudie het gewys dat in suider-Afrika, wildlewe-boerdery 'n lewensvatbare alternatief kan wees vir veeboerdery, veral in die droër streke wat 'n hoër reenval speling toon. Gebaseer op die verspreiding en digtheid van die meer algemene wild, gee hoofstuk drie 'n oorsig van die beskikbaarheid van hierdie hulpbronne. Trofeejag, wat die belangrikste inkomstesektor is, word bespreek, sowel as die lewende verkoop, uitvoer en nagoes (skiet van diere gedurende die nag vir vleisproduksie) van wild, asook die wildvleis produksie. Met betrekking tot die ekonomiese uitsette, word 'n vergelyking gemaak tussen die wildlewe en kommersiele veeboerdery industrie. Hoofstuk vier dek die finansiele modelering en ekonomiese aspekte van die wildlewe industrie in Namibie. 'n Rekenaar "spreadsheet" -gebaseerde, deterministiese model is ontwikkel om die kontantvloei van verskeie opsies van wildlewe boerdery te verken. Voorbeelde sluit in die gebruik van verskillende spesie samestellings, die besit van grond met verskillende drakrag vermoëns, asook die aanbiedinge van verskeie dienste. Hoofstuk vyf bespreek die beleid en wetgewing met betrekking tot die wildlewe industrie. Onderwerpe soos eiendomsreg en eksklusiewe benuttingsregte, industrie verteenwoordiging en die stigting van "smart" vennootskappe met primere hulpbron verbruikers, word aangespreek. Aanbevelings word aan die Ministerie van Omgewing en Toerisme gemaak. Hoofstuk ses behels 'n sintese van die voorafgaande vier hoofstukke.
510

Species utilisation preferences and resource potential of miombo woodlands : a case of selected villages in Tabora, Tanzania

Mbwambo, Lawrence Richard 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2000. / Full text to be digitised and attached to bibliographic record. / ENGLISH ABSTRACT: Miombo woodland occupies the greater portion of the Zambezian phytoregion where communities derive products and services for their livelihood. The managers of these resources have for many years neglected these crucial needs, which has important implications for silvicultural systems and management interventions. The overall objective of this study was to document the miombo species utilisation preferences by local communities in Tabora, Tanzania. This information was obtained using individual interviews and village meetings. A simple line transect inventory survey was carried out to assess the miombo resources adjacent to the studied villages. The villagers in Tabora have knowledge of the importance of their woodland resources and put different species to different uses, with some overlap where a species has multiple uses. The surveyed villages differ in the utilisation of miombo resources, where the choice and quantities used depend on their proximity to urban areas. There is strong preference for suitable species for building poles and due to scarcity some people now use mud bricks for house construction. Suitable timber tree species are scarce in the Urumwa Forest Reserve and now low quality species such as Sterculia quinqueloba are used. For firewood live trees are cut and dried, however any combustible material is used. Not surprisingly the community's use priorities differ from the management priorities of the Forest Department. The use of miombo products for income generation in the studied villages is influenced by the proximity to urban areas and villagers do not perceive commercialisation of these products as depriving them of resources. The use of woodlands for cultural and religious purposes in Tabora, though important to the spiritual wellbeing of people, has declined over the years. The fact that the villagers choose particular miombo trees for different purposes is an indication of some kind of local knowledge and management. The Urumwa Forest Reserve is now an open access resource as villagers have depleted wood resources adjacent to their settlements. Awareness of the causes of miombo resource depletion in these villages is positively correlated with the proximity to urban areas and wood scarcity. Community participation in management of natural resources is still new in Tabora as few villagers were aware of the new government management interventions of the Urumwa woodlands, and awareness seems to be limited largely to males and leaders. There is active management of indigenous trees protected on farms for various uses and exotic tree-planting mainly for fruits and shade, is done around homesteads, but with no de jure rights of ownership. Tree planting in this area is severely hindered by drought, insects and termite attack to seedlings and this has made people depend entirely on the miombo for their wood requirements. The simple wood resource inventory survey carried out in this study has showed that the Urumwa miombo woodland is heavily utilised. This has resulted in poor tree diameter distribution and species composition. The smaller tree diameters recorded in the Urumwa Reserve indicate that the potential of this woodland for timber production is low compared to other products. The priority products documented in this study form base-line information for management plans and silvicultural systems suitable for sustainable management and utilisation of these woodlands in future. / AFRIKAANSE OPSOMMING: Miombo bosveld beslaan die grootste gedeelte van die Zambezi vegetasiestreek waarin 'n groot menslike bevolking produkte en dienste uit hierdie bioom genereer om 'n bestaan te maak. Bestuurders van hierdie bronne verwaarloos al jare hierdie kritiese behoeftes, en dit het belangrike implikasies vir boskundige sisteme en bestuurstussentredes. Die hoofdoel van hierdie studie was om die miombo spesiesbenutting-voorkeure van plaaslike gemeenskappe in Tabora, Tanzanië te bepaal. Inligting is bekom deur individuele onderhoude en dorpsvergaderings. 'n Eenvoudige lyn-transek opname is uitgevoer om die miombo-bronne langs die bestudeerde dorpies te bepaal. Die dorpsbewoners in Tabora dra kennis van die belangrikheid van hul bosveld bronne en gebruik verskillende spesies vir verskillende doele, met oorvleuling waar spesies meervoudige gebruike het. Die dorpies wat ondersoek is verskil in die benutting van miombo bronne waar die keuses en kwantiteite wat gebruik word bepaal word deur die nabyheid aan stedelike gebiede. Daar is 'n sterk voorkeur vir spesies geskik vir boupale en as gevolg van skaarste van die spesies gebruik sommige inwoners nou klei bakstene vir huiskonstruksie. Geskikte spesies vir die produksie van hout is skaars in die Urumwa Forest Reserve en lae kwaliteit spesies soos Sterculia quinqueloba word gebruik. Lewende bome word gekap en gedroog vir brandhout alhoewel enige brandbare materiaalook gebruik word. Dit is nie verbasend dat die gemeenskap se gebruiksprioriteite verskil van die bestuurs-prioritiete van die Departement Bosbou nie. Die gebruik van miombo-produkte vir inkomste-generasie in die bestudeerde dorpies word beinvloed deur die nabyheid aan stedelike gebiede en dorpsbewoners beskou nie dat die kommersialisering van sulke produkte hul van hulpbronne ontneem nie. Die gebruik van bosveld vir kulturele en godsdienstige doeleindes in Tabora, wat belangrik is vir die geestelike gesondheid van die inwoners, het oor die jare afgeneem. Die feit dat dorpsbewoners besondere miombo-bome kies vir verskillende gebruike is 'n aanduiding van 'n mate van plaaslike kennis en bestuur. Die Urumwa Bosreserwe is nou 'n vrye toegang hulpbron omdat dorpsbewoners houtbronne na aan hul dorpies uitgeput het. Bewustheid van die oorsake van die uitputting van miombo hulpbronne naby die dorpies is positief gekorreleerd met die nabyheid aan dorpsgebiede en houtskaarste. Gemeenskapsdeelname by die bestuur van natuurlike hulpbronne is 'n nuwe konsep in Tabora omdat min dorpsbewoners bewus is van nuwe bestuursintredes deur die regering by die Urumwa bosveld en bewustheid blyk beperk te wees tot mans en leiers. Daar is aktiewe bestuur van inheemse bome wat vir spesefieke gebruike beskerm word op plase en uitheemse boomaanplantings, hoofsaaklik vir vrugte en skadu, word by huise gemaak. Daar is geen de jure regte in die geval nie. Boomaanplantings in die gebied word ernstig beperk deur droogte, insekte en termietaanvalle op saailinge en dit veroorsaak dat mense uitsluitlik op miombo staat maak vir hul houtbehoeftes. Die eenvoudige houthulpbron-opname wat in die studie onderneem is het bewys dat die Urumwa miombo bosveld strafbenut word en dat daar geen balans tussen aanwas en hout benutting is nie. Dit veroorsaak swak boomdeursnit-verspreiding en spesies samestelling. Die kleiner boomdeursnitte wat in die Urumwa Bosreserwe aangeteken is dui daarop dat die potensiaal van hierdie bosveld vir houtproduksie laag is en slegs beperk is tot ander produkte. Die voorkeur-produkte wat in hierdie studie gedokumenteer is vorm kerninligting vir bestuursplanne en boskundige sisteme wat geskik sal wees vir die toekomstige volhoubare bestuur en benutting van hierdie bosvelde.

Page generated in 0.0944 seconds