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  • 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.
11

Entrepreneurs and organisations: a case study of the Gisborne aquaculture cluster

Johnstone, Bruce Alexander January 2008 (has links)
This research contributes to the discussion surrounding New Zealand’s entrepreneurial environment and Innovation Framework and addresses the research problem of whether the New Zealand government should seek to support entrepreneurship and innovation through the various knowledge-based or regulatory organisations it owns or funds, and if so, how it should go about accomplishing this. The approach taken was to use qualitative methods to examine how the government’s support for entrepreneurship and innovation was delivered to an emerging cluster of entrepreneurs from the point of view of those entrepreneurs. The entrepreneurs were involved in the innovative industry of land-based aquaculture and fieldwork was carried out in the Gisborne Region, on the east coast of the North Island of New Zealand. This study began by reviewing relevant literature from academic, industry and government sources to identify relevant sub-themes and create a framework for analysis. Fieldwork was undertaken using ethnographic methods to explore how the entrepreneurs experienced the New Zealand entrepreneurial environment and innovation framework in their interactions with knowledge-based and regulatory organisations. Data was gathered primarily by participant observation and semi-structured interviews and transcripts were coded and analysed using NVivo® software. An ethnographic narrative was produced and the interview transcripts analysed for relevance to the sub-themes from literature and to identify patterns that emerged from the data. This research reports that four of the entrepreneurs failed in their ventures due to a combination of factors both within their operations and within the entrepreneurial environment. These factors included technical difficulties maintaining livestock health and growth within an artificial marine environment, an inability to obtain assistance from knowledge-based organisations, problems in dealing with regulatory organisations, difficulty retaining trained staff, uncertainty about the market, and high energy costs. The Māori training organisation, Turanga Ararau, formed the Gisborne Aquaculture Society in an effort to establish a Gisborne aquaculture cluster however, this initiative proved unsuccessful primarily because the society failed to attract the 12 involvement of key stakeholders. This research contributes to the policy and practice of cluster facilitation by examining the extent to which best practice was followed in this attempt to establish a cluster and presents conclusions as to how the process of establishing the cluster could have been improved. This study also reports that the entrepreneurs were cut off from access to knowledge and research resources and received little advice or support from the knowledge based organisations that might have played a role in the development of their cluster. It examines how and why New Zealand’s Innovation Framework might be failing to recognise and support the vital role of entrepreneurs in economic development and suggests how this might be improved. The methodology chapters of this thesis contribute to literature regarding the use of ethnographic methods in entrepreneurship research and a further by-product of this thesis is an ethnographic account of the participant observation and semi structured interviews with the entrepreneurs. This research also provides an insight into the obstacles and challenges faced by entrepreneurs in New Zealand, in particular those involved in the emerging recirculating aquaculture industry.
12

16S ribosomal DNA analysis of marine ammonia-oxidising bacteria

McCaig, Allison E. January 1995 (has links)
Nitrification is central to the global cycling of nitrogen and is important for primary production and other processes in marine systems, where nitrogen is generally the limiting nutrient. The majority of studies on nitrification, however, have focused on terrestrial systems, where this process can cause significant losses of N-based fertilisers from agricultural land. Comparatively little is known of nitrification in marine systems and the organisms involved. In addition, technical difficulties in isolation of pure cultures of ammonia-oxidising bacteria have severely restricted studies of species diversity and community structure of these organisms. In this study, molecular technology, based on the 16S ribosomal RNA (rRNA) molecule was applied to the characterisation of marine communities of ammonia-oxidising bacteria. PCR primers were designed for specific amplification of the rRNA gene (rDNA) from ammonia-oxidisers belonging to the beta-subdivision of the Proteobacteria. These primers were used to characterise both enrichment cultures and communities within polluted and unpolluted sediment samples. These studies indicated considerable diversity of beta-subgroup ammonia-oxidisers within marine systems which has not previously been detected. It was also shown that enrichment and isolation techniques select for strains belonging to the genus Nitrosomonas while the majority of sequences obtained by direct analysis of rDNA amplified from total genomic extracts belonged to the genus Nitrosospira. In addition, novel isolation methods were developed which considerably reduced the level of heterotrophic contamination and greatly facilitated isolation of pure cultures. In situ probing, using fluorescently labelled rRNA oligonucleotide probes, indicated that CCD microscopy is less sensitive than UV microscopy alone due to quenching of the signal.
13

Estudos morfológicos e histoquímicos do tubo digestivo de Hemisorubim platyrhynchos (Valenciennes, 1840)

Faccioli, Claudemir Kuhn [UNESP] 30 January 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:22:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-30Bitstream added on 2014-06-13T19:07:47Z : No. of bitstreams: 1 faccioli_ck_me_jabo.pdf: 2072027 bytes, checksum: 58de1d06e05f35b0cac0a9f1b883972d (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O conhecimento das características morfológicas do tubo digestivo, associado aos processos de digestão e absorção, é essencial para a compreensão da fisiologia e nutrição de peixes, auxiliando no planejamento de dietas para a criação e manejo de animais com potencial para piscicultura. Assim sendo, este trabalho descreveu o tubo digestivo de Hemisorubim platyrhynchos, por meio de estudos macroscópicos, histológicos, histoquímicos de mucossubstâncias e ultraestruturais (microscopia eletrônica de varredura e de transmissão). A estrutura do tubo digestivo de H. platyrhynchos é típica de peixes carnívoros, composta por esôfago curto e distensível, estômago volumoso e muscular e intestino curto, com pregas longitudinais que diminuem em direção à região posterior. O esôfago apresentou a camada mucosa revestida por epitélio estratificado pavimentoso, cujas células epiteliais em MET mostraram microssaliências digitiformes, além de “club cells” com citoplasma homogêneo e poucas organelas e células caliciformes com citoplasma repleto de grânulos de secreção. O estômago foi morfologicamente dividido em região cárdica, fúndica e pilórica, com camada mucosa composta por epitélio simples colunar (com mucossubstâncias apicais protetoras) e porção glandular bem desenvolvida nas regiões cárdica e fúndica. A região pilórica aglandular apresentou camada muscular espessa (esfíncter pilórico). O intestino apresentou epitélio simples colunar e células caliciformes aumentando em número na região posterior. As células secretoras apresentaram características morfológicas e histoquímicas distintas em cada segmento do tubo digestivo: células caliciformes esofágicas (muco neutro e ácido, carboxilado e sulfatado); células epiteliais gástricas (muco neutro); células caliciformes no intestino anterior, médio, posterior e células epiteliais na região retal (muco neutro e ácido, carboxilado e sulfatado) / The knowledge of the morphological features of the digestive tract, associated with the digestion and absorption processes is essential for the understanding of fish nutrition and physiology, assisting in planning diets for the rearing and management of animals with potential for fish farming. Therefore, this paper describes the digestive tract of Hemisorubim platyrhynchos, by macroscopic, histological, histochemical of mucosubstances and ultrastructural studies (scanning and transmission electron microscopy). The structure of the digestive tract of H. platyrhynchos is typical of carnivorous fish, consisting of short and distensible esophagus, large and muscular stomach, and short intestine with longitudinal folds which decrease towards the posterior region. The esophagus presented the mucosa layer lined by stratified squamous epithelium, which epithelial cells in MET showed fingerprint-like microridges, club cells with homogeneous cytoplasm and few organelles and goblet cells filled with secretion granules. The stomach was morphologically divided into the region cardic, fundic and pyloric, with the mucosa layer composed of simple columnar epithelium (with protective mucosubstances apical) and well-developed glandular portion of the cardic and fundic regions. The aglandular pyloric region showed thick muscular layer (pyloric sphincter). The intestine showed simple columnar epithelium and goblet cells increasing in number in the posterior region. The secretory cells showed distinct morphological and histochemical features in each segment of the digestive tract: esophageal goblet cells (neutral and acid mucus, carboxylated and sulfated), gastric epithelial cells (mucus neutral), goblet cells in the anterior, middle and posterior intestine and epithelial cells in the rectal portion (neutral and acid mucus, carboxylated and sulfated)
14

Contribution of small scale fish farming subsector to rural income generation in Thulamela Municipality in Limpopo Province, South Africa

Phosa, Moatladi Jacob January 2018 (has links)
Thesis (M.Dev.) --University of Limpopo, 2018 / The purpose of this study was to investigate the contribution of small-scale fish farming sub-sector to rural income generation in Thulamela Municipality in Limpopo Province, South Africa.The study applied a qualitative method to collect data from individual respondents of same characteristics using the semi-structured interview involving 15 small scale fish farmers. The findings from the study revealed that in terms of gender, more men were participating in the fish farming sector than women. About 73 percent of the total participants were men as compared to 27 percent of women participating in fish farming. In terms of age, a large proportion of farmers were men and women within the age range of 41-50 years and above 50 years who participated more actively in fish farming than other age groups. The results revealed some challenges and constraints characterised by theft of fish by community members, fish-eating birds or predators, poor access to funding, expensive fish feed, unavailability of fish feed, shortage of land, lack of proper infrastructure, and insufficient water supply during the drought period. As part of recommendations, some interventions should be developed to address the constraints and challenges revealed in the study. Small-scale fish farmers should be assisted to have access to proper infrastructure, boreholes to supplement available water during the dry season, fish feed, the agricultural market, land and other resources for fish farming.
15

study on the devdlopment of net-cage fish-farming in Taiwan

Yang, Bo-ren 26 July 2002 (has links)
There are many approach for The study of marine resources and now in Taiwan is a lot of express , but the damage to net-cage by typhoon is cost much money . The most important study in Taiwan is to use new teconology to update the traditional business and get advanture in international.
16

Ajuste do fornecimento automático de ração de acordo com a temperatura da água para tilápias criadas em tanques rede / Adjustment of the automatic feed supply according to the water temperature for tilapia created in net tanks

Carmelin, Celio Aparecido [UNESP] 15 July 2018 (has links)
Submitted by Célio Aparecido Carmelin Júnior (celiomestre@gmail.com) on 2018-07-10T18:31:47Z No. of bitstreams: 1 tese final corrigida com ficha.pdf: 629321 bytes, checksum: ddbd36bb4fb86650c0001be1f8c96d04 (MD5) / Approved for entry into archive by Sulamita Selma C Colnago null (sulamita@btu.unesp.br) on 2018-07-16T16:59:10Z (GMT) No. of bitstreams: 1 carmelin_ca_dr_bot.pdf: 629321 bytes, checksum: ddbd36bb4fb86650c0001be1f8c96d04 (MD5) / Made available in DSpace on 2018-07-16T16:59:10Z (GMT). No. of bitstreams: 1 carmelin_ca_dr_bot.pdf: 629321 bytes, checksum: ddbd36bb4fb86650c0001be1f8c96d04 (MD5) Previous issue date: 2018-07-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O estudo teve como objetivo avaliar o fornecimento automático de ração em diferentes períodos para tilápias (Oreochromis niloticus), em diferentes situações ao longo do ano. Foram realizados dois trabalhos, o primeiro objetivou-se avaliar o desempenho de tilápias criadas sob efeito de altas temperaturas, em dois períodos diferentes, sendo o período 1 (0:00 ao 12:00hs) e o período 2 (12:00 a 24:00hs), entre os dias 15 de janeiro e 8 de março de 2017. Os melhores resultados para ganho de peso, peso total e peso médio foram encontrados nos peixes alimentados durante o período 1. Portanto, orienta-se fornecer o alimento, utilizando-se o sistema proposto, durante o período 1, para animais criados sob condições climáticas semelhantes às do experimento. O segundo trabalho teve como objetivo avaliar o desempenho de tilápias criadas sob efeito de baixas temperaturas, em três períodos diferentes, sendo o período 1, (0:00 ao 12:00hs) o período 2 (12:00 às 24:00hs) e o período 3 (0:00 às 24:00hs), entre os dias 4 de abril e 15 de julho de 2017. Os melhores resultados para ganho de peso e peso total foram obtidos pelos animais alimentados durante o período 2. O pior tratamento foi o período 1 e o período 3 foi intermediário. Portanto, orienta-se fornecer o alimento, utilizando-se o sistema proposto, durante o período 2, para animais criados sob condições climáticas semelhantes às do experimento. / The objective of this study was to evaluate the automatic feed supply in different periods for tilapia (Oreochromis niloticus), in different situations throughout the year. Two studies were carried out. The objective of the first study was to evaluate the performance of tilapia grown under high temperature conditions in two different periods: period 1 (0:00 to 12:00) and period 2 (12:00 to 24:00), between January 15 and March 8, 2017. The best results for weight gain, total weight and average weight were found in fish fed during period 1. Therefore, it is advised to provide the feed using the system proposed, during period 1, for animals reared under climatic conditions similar to those of the experiment. The second study had as objective to evaluate the performance of tilapia created under effect of low temperature, in three different periods, period 1 (0:00 to 12:00) period 2 (12:00 to 24:00) and the period 3 (0:00 to 24:00), from April 4 to July 15, 2017. The best results for weight gain and total weight were obtained by animals fed during period 2. The worst treatment was period 1 and period 3 was intermediate. Therefore, it is advised to provide the feed, using the proposed system, during period 2, for animals raised under climatic conditions similar to those of the experiment.
17

Tasteless, Cheap, and Southern?: The Rise and Decline of the Farm-Raised Catfish Industry

Senaga, Karen 07 May 2016 (has links)
This dissertation traces the rise and recent decline of the farm-raised catfish industry. From the 1960s to the 2000s, farmers and scientists reengineered the river catfish into an agro-industrial food crop. Through extensive agricultural scientific research and marketing, the farmed catfish industry changed the history of the animal, its image, its flesh and bone, its natural environment, and its place in society all by changing—or in an effort to change—its taste. This process moved the catfish from the ranks of a muddy tasting wild fish mainly associated with the poor, to a tasteless, cheap food consumed by all classes and ethnicities. Former cotton planters dug ponds and raised the fish, as researchers at land-grant universities gave the fish a taste and image makeover. Developing a bland meat and an efficient way to grow it presented only half the problem. Workers, predominately black, poor, and female, slaved away in dank, dangerous processing plants. Some struck, despite labor power’s impotence in a globalizing economy. Amid these labor disputes, competition from Vietnamese catfish imports began to trickle in onto the American seafood market. By the 2000s, the “Catfish Wars” had broken out between Asian importers and American farmers. Processors devised quality control measures that washed away the catfish’s distinctive qualities. They had done their work so well, that consumers could tell no difference between fish from around the globe. The farm-raised catfish embodied a culinary, cultural, and technological transformation. My work shows the importance of sensory experiences to southern culture, foodways, African American history, environmental history, and agricultural history.
18

Characterization, Treatment, and Improvement of Aquacultural Effluents

Maillard, Vincent M. 11 January 1999 (has links)
During the water quality and sludge characterization phase, average effluent quality over the course of a day was not found to be impaired during a 7-month sampling and monitoring study at the three trout farms. However, effluent quality was found to change significantly during times of high farm activity (i.e. feeding, harvesting, cleaning, etc.). Normalized Total Suspended Solids (TSS) concentrations were found to be as high as 115 mg/l during harvesting and 63 mg/l during feeding. Solids characterization studies proved farm waste solids degrade over time and that their particle size distributions are a function of the feed size and activity of a certain raceway. Waste solids accumulation studies proved that the solids removal efficiency of farm sediment traps were very low, and after a certain period of time, they reached capacity due to particle scouring. A pilot plant was constructed in the water and sludge treatability phase to prove a baffled settling scheme was sufficient to treat average and peak TSS concentrations during a normal workweek. The study found optimal TSS removals at detention times of 15-20 minutes, and overflow rates of 77.4 – 48.9 m3/m2·d. Given economic, spatial, and operational constraints, sedimentation was found to be the most feasible treatment technology for raceway-system trout farms. / Master of Science
19

Odlad fisk : Konsumentens kunskap om fiskodling

Arvidsson, Mathilda, Naenfeldt Eklund, Kim, Tavelin, Emma January 2013 (has links)
Fisk är ett hälsosamt livsmedel och allt eftersom världsbefolkningen har växt och hälsotrenden blossat upp, har trycket på fiskerinäringen ökat. Bakgrundens fakta tog upp olika konsekvenser som fiskodling kan medföra och hur stor kunskap konsumenten har om detta och deras makt att påverka industrin. Syftet med studien var att belysa brister i fiskodling kopplat till konsumenters kunskap, samt hur de etiska frågorna påverkar konsumentens val. I metod och materialstycket lades det fram att studien var en litteraturstudie som baserades på vetenskapliga artiklar från olika databaser som gick att tillgå vid Örebro universitet. Resultatet av undersökningen gav inblickar i vad konsumenter visste om odlad fisk, vad de tyckte om produkten och hur eller om de utövade sin makt. Resultatet visar även hur hanteringen av fisk går till på fiskodlingar runt om i Europa. I diskussionsavsnittet i studien lades bakgrundsfakta ihop med fakta ur resultatavsnittet. I diskussionen framkom information om att konsumenters uppfattning och kännedom om odlad fisk inte var tillräcklig, trots de märkningar och informationskällor som presenteras i bakgrunden.I diskussionsavsnittet diskuteras även processen som ledde fram till den här studien och vad som fungerat respektive inte fungerat. / B-uppsatser
20

Detecção e caracterização moleculares do Vírus da Viremia Primaveril da Carpa em peixes de água doce das regiões nordeste e centro-leste do estado de São Paulo / Molecular detection and characterization of the Spring Viremia of Carpa Virus in fresh fish from the northeast and central west regions of the state of São Paulo

Arruda, Eurico de Paula 16 December 2015 (has links)
Piscicultura de água doce consiste na maior produção da aquicultura mundial e o cultivo de peixes tem crescido, devido a investimento, desenvolvimento de tecnologias e à contínua expansão de espécies cultivadas. Esse aumento gerou novas possibilidades de transmissão de vírus aquáticos, fatores limitantes à produção da aquicultura. Dentre as centenas de vírus conhecidos de peixes, um dos principais, que atualmente é de preocupação internacional, é o vírus da Viremia Primaveril da Carpa (SVCV), devido a sua importância socioeconômica considerando os países afetados e o comércio internacional de animais aquáticos e seus derivados, com base na saúde e medidas preventivas. SVC é uma doença aguda causada por um rhabdovírus do gênero Vesiculovirus, que é um vírus de ácido ribonucleico (RNA) fita simples linear de aproximadamente 11 quilobases (kb) com polaridade negativa e envelopado. Diversos ensaios diagnósticos podem ser utilizados para detectar SVCV, porém, consomem tempo e não são adaptados para diagnóstico a campo. A prevenção da disseminação do vírus é crucial; portanto, maior entendimento do vírus e de sua transmissão é necessário. No presente estudo, a padronização de uma RT-nestedPCR foi realizada, cujo limite de detecção foi de 8,62 × 10-2 cópias/reação, observado após o spiking de tecidos de peixes com diluições seriadas de um controle positivo sintético. O ensaio foi aplicado a 150 amostras teciduais provenientes de 146 peixes distintos. As amostras consistiam de fragmentos de fígado, rim e baço e foram submetidas à transcrição reversa (RT), seguida pela reação em cadeia de polimerase (PCR), em configuração nested. Duas (2) amostras foram positivas para o gene G de SVCV pela RT-nestedPCR e a identidade dos produtos obtidos foi confirmada por sequenciamento direto utilizando-se o método de Sanger. Na reconstrução filogenética, as sequências obtidas formaram clado único, separado dos demais genogrupos e mesmo de sequências derivadas de outros vesiculovírus encontrados no Brasil. Esses resultados determinam a primeira detecção e caracterização moleculares de SVCV no Brasil por RT-nestedPCR e sequenciamento nucleotídico, indicando a necessidade de adoção de medidas de biosseguridade mais restritivas na produção pesqueira nacional. / Fresh-water fish farming forms the largest portion of the world aquaculture production, and the harvest of these warm-water fish is increasing, due to investment, improvement of technologies and continued expansion of cultivated species. This increase has rendered new possibilities for the transmission of aquatic viruses, which remain limiting factors for aquaculture production. Among the hundreds of known viruses of fish, one of the main viruses that are currently of international concern is the Spring Viremia of Carp virus (SVCV) due to its socio-economic importance regarding affected countries and international trade of aquatic animals and their products, on the basis of health control and preventive measures. SVC is an acute disease, caused by a rhabdovirus, belonging to the Vesiculovirus genus, and is an enveloped virus, with a linear single-strained negative-sense ribonucleic acid (RNA) of approximately 11 kilobases (kb). Several diagnostic assays are available for the detection of SVCV, but they are time-consuming and not well adapted for field diagnosis. Prevention of spreading of the virus is crucial; therefore, more understanding of the virus and its transmission is required. In this study, standardization of a RT-nestedPCR was performed, and its detection limit was of 8.62 × 10-2 copies/reaction, observed after spiking fish tissue with serial dilutions of a synthetic positive control. The assay was applied to 150 tissue samples from 146 different fish. Samples consisted of liver, kidney and spleen fragments, and underwent reverse transcription (RT) followed by the polymerase chain reaction (PCR) of a nested configuration. Two (2) tissue samples were found positive for the G gene of SVCV by RT-nestedPCR and the identity of products was confirmed by direct sequencing using the Sanger method. By phylogenetic reconstruction, the obtained sequences formed a unique clade, separating them from the other known genogroups, and even from sequences derived from other vesiculoviruses found in Brazil. These results represent the first molecular detection and characterization of SVCV in Brazil by RT-nestedPCR and nucleotide sequencing, indicating the need to adopt more stringent biosecurity measures in national fish farming production.

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