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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.
1

Determinants of natural fertility differentials : a comparative study of the rural populations of the Inner Niger Delta of Mali

Marriott, Heidi January 1993 (has links)
No description available.
2

Agroforestry Practice Adoption Among Solomon Island Women On The Island Of Malaita

Sechrest, Etta K 01 December 2008 (has links)
The goal of agricultural training is the adoption and diffusion of introduced agriculture techniques. New subsistence agricultural techniques have been introduced mainly to the male population in many developing countries, even though most subsistence farmers are women. Therefore, an understanding of how new subsistence agricultural techniques can be introduced and adopted by women would be important to achieve. This study focuses on women's adoption of agricultural techniques. It takes place on the island of Malaita, in the Solomon Islands. The study looks at the adoption of agroforestry and several other subsistence techniques that were introduced under a joint program by Peace Corps and the Malaita Agriculture Division between 1983 and 1989. Two Peace Corps volunteers were posted in North Malaita at Malu'u from 1983 to 1986. The Malu'u volunteers lived in the village of Karu for two and one-half years while introducing and teaching new agricultural practices. Two other Peace Corps volunteers were posted at the Dala Agricultural Training Center from 1987 to 1989, and worked with the residents of the nearby village of Kakara. In 1991, a two-month survey was conducted in the areas where the Peace Corps volunteers were posted, as well as in an area that did not have any Peace Corps volunteers posted. The findings of this study indicate that adoption of new agroforestry techniques is based on several factors. Who introduced the technology, the farmer's wealth, and being able to obtain income from market vegetables and other identified factors improved a respondent's chances of adopting new agroforestry techniques.
3

Subsistence Farmers' Perceptions of Pluralistic Agriculture Extension in Northern Ghana

Baah, Amos Kwame Egyir 01 January 2017 (has links)
In 2013, the Ministry of Food and Agriculture of the Republic of Ghana implemented a reformed food and agriculture sector development policy (FASDEP II) to reduce poverty among the poorest subsistence farmers in the nation. These extension efforts have been unsuccessful. The purpose of this ethnographic case study was to understand the perceptions of subsistence farmers in the Savelugu-Nanton District (SND) who participated in FASDEP II on how the program had affected their ability to meet their subsistence needs. The theoretical framework of collaborative advantage was used to analyze farmers' opinions of how the decentralized, pluralistic extension policy did or did not result in effective collaborations to benefit both farmers and support organizations. Data from unstructured interviews with 12 male farmers, selected through purposeful sampling, were analyzed by inductive coding and thematic analysis. Farmers' perspectives were confirmed through observations at a public farmers' meeting and a review of operations documents of Busaka, a FASDEP II agribusiness partner. Key findings indicated that the current pluralistic extension lacked the characteristics of collaborative advantage and farmers continued to face challenges in access to farming inputs, credit, climate change effects, and cronyism. Farmers perceived the system was more beneficial to large-scale farmers. Positive social change implications of this study include identifying factors to improve effective pluralistic extension for subsistence farmers, the poorest persons in SND; improving the financial conditions of these subsistence farmers through more sustained and equitable partner collaboration; and contributing to the economic development of SND.
4

Fumonisin exposure biomarkers in humans consuming maize staple diets

Van der Westhuizen, Liana 03 1900 (has links)
Thesis (PhD (MedSc))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Fumonisins are carcinogenic mycotoxins which occur world-wide in maize and maize-based products intended for human consumption. Consumption of fumonisin contaminated maize as a staple diet has been associated with oesophageal and liver cancer incidence as well as neural tube defects. This study has confirmed the State of Santa Catarina, Brazil as another region where the consumption of maize contaminated with fumonisins and high oesophageal cancer incidence co-occur. Since fumonisins exert their main biochemical effect by disruption of the sphingolipid biosynthetic pathway and are implicated in cancer, the role of fumonisin B1 (FB1) in FB1–induced rat hepatocyte nodules was investigated. The current study showed that FB1 exposure activated sphingosine accumulation in the nodules which could induce the bio-active sphingosine 1-phosphate to provide a selective growth stimulus on subsequent FB1 exposure. Since the FB1-induced hepatocyte nodules were not resistant to the disruption of sphingolipid biosynthesis, it was not the mechanism whereby the altered hepatocytes escaped the mitoinhibition of FB1 and selectively proliferated into hepatocyte nodules. A study in maize subsistence farming communities investigated the sphingosine and sphinganine levels in blood and urine of participants. Fumonisin exposure was assessed in these communities based on fumonisin levels in maize that was concurrently collected from the areas where the participants resided. Subsequently fumonisin exposure was assessed in individuals based on the fumonisin levels in maize collected from each household and by acquiring weighed food records for each member of the household. It was confirmed in both these studies that communities are chronically exposed to fumonisin levels well above the provisional maximum tolerable daily intake determined by the Joint FAO/WHO Expert Committee on Food Additives. Since the sphinganine and sphingosine levels in blood and urine of the participants exposed to various levels of fumonisin were not significantly different, the sphingoid bases and their ratios could not be established as a biomarker of fumonisin exposure. Therefore, an alternative biomarker of exposure was investigated during studies into a practical cost effective method to reduce fumonisin. The customary maize food preparation practices were assessed in a maize subsistence farming community and subsequently optimised to reduce the fumonisin levels in the maize under laboratory-controlled conditions. Implementation of this optimised and culturally acceptable intervention method of sorting and washing maize in a rural community reduced fumonisin contamination in home-grown maize by 84%. The intervention study attained a 62% reduction in fumonisin exposure based on fumonisin levels in maize-based food and consumption as assessed by 24-h dietary recall questionnaires. The alternative biomarker of fumonisin exposure, urinary FB1, was investigated during the intervention study. The FB1 urinary biomarker measured fumonisin intake at the individual level and confirmed the reduction achieved as assessed by food analysis and food intake data. The biomarker was thus well correlated with fumonisin exposure and confirmed the efficacy of the simple and culturally acceptable intervention method. Utilisation of the urinary FB1 biomarker and the customised hand-sorting and washing of maize to reduce fumonisin exposures has the potential to improve food safety and health in subsistence maize farming communities. / AFRIKAANSE OPSOMMING: Fumonisien is kankerverwekkende mikotoksiene wat wêreldwyd voorkom op mielies en mielie-verwante produkte bestem vir menslike verbruik. Daar is ‘n verband tussen die voorkoms van slukderm en lewer kanker, sowel as neuraalbuisdefekte, in gemeenskappe waar fumonisien-gekontamineerde mielies die stapel voedsel is. Die Brasiliaanse Staat, Santa Catarina is uitgewys as nog 'n area waar hoë voorkoms van slukdermkanker en hoë fumonisin vlakke in mielies gesamentlik voorkom. Aangesien fumonisien verbind word met van kanker en die hoof biochemiese effek die ontwrigting van die sfingolipiedbiosintese weg is, is die rol van fumonisien B1 (FB1) in FB1-geinduseerde rot hepatosietnodules ondersoek. Die studie het getoon dat FB1 blootstelling aktiveer sfingosien ophoping in die hepatosietnodules wat moontlik die bio-aktiewe sfingosien 1-fosfaat aktiveer om op daaropvolgende FB1 blootstellings geselekteerde groei stimulasie te ondergaan. Die FB1-geïnduseerde hepatosietnodules was nie bestand teen die inhibisie van die sfingolipied biosintese nie en dus nie die meganisme waardeur die veranderde hepatosiete mito- inhibisie van FB1 vryspring, en selektief ontwikkel in hepatosietnodules nie. ‘n Studie in bestaansboerdery gemeenskappe het die sfingosien en sfinganien vlakke in bloed en uriene vergelyk met individuele fumonisien blootstelling. Laasgenoemde is gebaseer op fumonisien vlakke in gekolleekterde mielies vanuit die deelnemers se huise en aannames vanuit die literatuur. Die opvolg studie in die areas het individuele fumonisien blootstelling bepaal gebaseer op fumonisien vlakke in die mielies van elke huishouding en die inname van mielies deur die voedsel van elke individu te weeg. Albei hierdie studies het bevestig dat die gemeenskappe blootgestel is aan kroniese fumonisien vlakke wat die maksimum toelaatbare daaglikse inname wat deur die gesamentlike FAO/WHO deskundige komitee op voedsel toevoegsels vasgestel is, oorskei. Aangesien die sfingosien en sfinganien vlakke nie beduidend verskil in bloed of uriene van mense wat aan verskillende fumonisien-kontaminasie vlakke blootgestel is nie, kan die lipiedbasisse en hul verhouding nie as ‘n biologiese merker vir fumonisien blootstelling bevestig word nie. Dus is ‘n alternatiewe biologiese merker vir fumonisien blootstelling ondersoek gedurende ‘n studie oor praktiese bekostigbare maniere om fumonisin blootstelling te verlaag. Die tradisionele voedsel voorbereidingspraktyke in ‘n bestaansboerdery gemeenskap is bestudeer en onder laboratorium-gekontroleerde toestande aangepas om fumonisien vlakke in die mielies optimaal te verlaag. Die kultureel aanvaarbare intervensie metode, sortering en was van die mielies, is in ‘n bestaansboerdery gemeenskap toegepas waar ‘n 84% verlaging in fumonisien vlakke van die mielies verkry is. Die intervensie metode het ‘n 62% verlaging in fumonisien blootstelling te weeggebring deur fumonisien vlakke in die mieliegebasserde disse te meet en inname daarvan deur die deelnemers met 24-h diëetkundige vraelyste vas t e stel. Gedurende die intervensie studie is urienêre FB1, die alternatiwe biologiese merker van fumonisien blootstelling, ondersoek. Individuele fumonisien blootstelling data, bepaal met die urienêre FB1 biomerker, het goed ooreengestem met die voedsel analise en voedsel inname data en het dus die doeltreffendheid van die praktiese kultuur aanvaarbare intervensie metode bevestig. Benutting van die FB1 urienêre biologies merker en die optimale sortering en was van die mielies om die fumonisien blootstelling te verlaag het die potensiaal om voedselveiligheid en gesondheid in hierdie bestaansboerdery gemeenskappe aansienlik te verbeter.
5

An exploratory study of psychological resilience factors associated with climate change adaptation by subsistence farmers in a rural community in Maruleng, Limpopo Province

Kgopa, Bontle Patience January 2022 (has links)
Thesis (Ph.D. (Psychology)) -- University of Limpopo, 2022 / Climate change poses a major threat to both the well-being of people and the environment. Subsistence farmers are particularly affected because they rely on local supply systems that are sensitive to climate variation. The aim of the study was to explore psychological resilience factors associated with climate change adaptation by subsistence farmers in a rural farming community in Maruleng Municipality in Limpopo Province (South Africa). The objectives of the study were to: investigate subsistence farmers' notions of climate change and adaptation; determine the psychological resilience factors influencing the farmers’ adaptation the climate change; determine strategies that the farmers use to cope with climate change; and, based on the farmers’ notions of climate change and adaptation, and the associated resilience factors, develop a psychological explanatory model on climate change adaptation by subsistence farmers. Data were collected through direct interactions with participants using a grounded theory research design. An open-ended interview guide was used to collect data with a sample of 15 participants selected through theoretical sampling within the Maruleng Municipality. The research findings indicate that farmers have limited conceptual knowledge relating to climate change and its causes. The results further indicated that participants have become resilient to climate change through mitigation strategies including mulching, adaptive irrigation techniques and being innovative. From a psychological perspective, the subsistence farmers’ resilience factors that emerged included passion for farming, hope, enthusiasm, courage, acceptance or tolerance, livelihood and a coherent belief system. Based on the findings of the study, a psychological explanatory model in climate change adaptation by subsistence farmers was developed. The explanatory model suggests that resilience factors are influenced by notions and adaptations of climate change. The study is concluded by, among others, recommending that counseling services be made available to farmers to help them deal with the stress associated with the negative impact of climate change.
6

Preliminary investigation of the natural contamination of agricultural crops with selected mycotoxins in northern rural South Africa (Limpopo and Mpumalanga Provinces)

Mngqawa, Pamella January 2013 (has links)
>Magister Scientiae - MSc / Subsistence farmers may contribute significantly to food production, food security, and employment in South Africa. However poor storage practices and contamination with mycotoxins, particularly fumonisins and aflatoxins impacts adversely on production, food safety and food security. Mycotoxins are toxic natural food-borne compounds which frequently contaminate agricultural produce worldwide. They are hazardous to humans and animals and result in significant production losses for farmers. This study focused on former Bantustans in Northern South Africa, namely Vhembe District Municipality (Limpopo) and Gert Sibande District Municipality (Mpumalanga). The aim was to assess mycological and mycotoxin contamination of crops grown by subsistence farmers. A semi-structured questionnaire was administered to randomly thirty-nine households. Data on demographics, storage practices and production during period of 2011 and 2012 cropping seasons were collected. One hundred and fifteen (115) crop samples (maize, beans and peanuts) were collected for analysis. Standard mycological methods and validated mycotoxin analysis methods (HPLC and LC- MS/MS) were used. It was found that maize was the staple food in both provinces, with a significant difference (p = 0.0184) in its production between the two districts; Vhembe produced 0.6 tonnes compared to 2.4 tonnes in Gert Sibande. The majority of the farmers for storage used traditional open wooden cribs (15/20) and steel tanks (5/20) while VDM farmers used sealed store houses 5/19 and 15/19 used polystyrene sacks. Aflatoxin occurrence was low with <1% of GSDM samples contaminated compared to 11% of VDM samples. No significant difference (p > 0.05) was observed in the aflatoxin contamination in VDM samples between the year 2011 and 2012. Samples from VDM households had higher Aspergillus fungal infection (maximum incidence 69%) compared to GSDM (27%) over both seasons. The most frequently isolated Fusarium species in VDM samples was F. verticillioides (92%; 93%), and F. subglutinans (97%; 80%) in GSDM samples over seasons 2011 and 2012, respectively. Highest levels of fumonisins (FB1+ FB2) ranged between 1010 μg/kg and 12168 μg/kg with less than 30% extremely contaminated above the regulated limit in 91% of samples from Limpopo over both seasons (2011 and 2012). Fumonisin levels between the two seasons in VDM showed no significant difference (p>0.05). Only three (less than 5%) from 68% GSDM contaminated maize samples were above the FB1 and FB2 limit. In 2011, there were two highly contaminated maize samples (1762 μg/kg and 4598 μg/kg) with the other samples less than 600 μg/kg, whereas in season two (2012) all samples were below 200 μg/kg, except one highly contaminated sample (26115 μg/kg). None of the beans and peanuts from Mpumalanga was contaminated with mycotoxins above the recommended limit, but from Limpopo 1/5 peanuts was found contaminated with aflatoxin G1 (41 μg/kg). Natural occurrence and contamination of both fumonisin and aflatoxin in stored home-grown maize from VDM was significantly (p < 0.0001) higher than GSDM over both seasons. In general, Limpopo farmers’ experience lower harvests and greater mycotoxin contamination of agricultural produce. This may be attributed in part to poor storage practices and environmental and climatic conditions in that agro-ecological zone.

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