23 research outputs found
Variability and repeatability of olfactometric results of n-butanol, pig odour and a synthetic gas mixture
No full textFor the purposes of a research project for the Flemish authorities, olfactometric measurements were carried out at six closed pig farms and six fattener farms. The results of these olfactometric measurements were compared with the olfactometric results of n-butanol samples and samples of a synthetic gas mixture of ethanethiol, methylacetate and 2-propanol in nitrogen, both analysed on the same days as the air samples from the pig farms. The results of the n-butanol tests for all panellists showed that nobody was qualified according to the CEN criteria, and that, consequently, these criteria are rather stringent. Comparing the variability of the results for the three different odours showed that the mean and standard deviation of the mean variance were not significantly different for the three odour types, which means that the repeatability of the panellist results was equal for the examined odour types. The principle of traceability was checked by comparing the variance of the n-butanol, pig odour and synthetic mixture ratio. For the complete dataset, the principle of traceability could not been proven for n-butanol. For the restricted dataset, the principle of traceability was more valid for n-butanol than for the mixture, but differences were small. Finally, normalization was looked for with regard to olfactometric measurements of air samples from pig farms based either on n-butanol or on the synthetic mixture. Both models had low determination coefficients, but the model based on the synthetic mixture gave better results than the one based on n-butanol.</jats:p
Performing virtual pilgrimage to Rome : a rediscovered Christ crucified from a series of three panel paintings (ca. 1500)
No full textPilgrimage is one of the most indispensable aspects to consider when determining the function of late medieval imagery, especially images that are related to indulgences. Some of them have been examined as an aid to perform pilgrimage without the hardship of an actual journey a virtual pilgrimage through which one could earn indulgences. Prominent examples are the small panels with Saint fohn the Baptist with a letter 'A in Museum Catharijneconvent in Utrecht, and the Virgin and Child with a letter 'D' in the Bob Jones University Museum and Gallery in Greenville. The first was thoroughly examined in 1981 by Henri Defoer, who compared the panel with an illustration of Die costelijke scat der gheestelijker rijcdoem (Heavenly treasure of spiritual wealth), which was a pilgrimage guide to Rome, especially to the Seven Pilgrimage Churches in Rome. On the basis of the subject and its letter, Defoer concluded that the panel shows San Giovanni in Laterano. The second was reported by Catherine Reynolds in 1997 as a panel with Santa Maria Maggiore.
This article presents for the first time a third panel, that was recently rediscovered in a private collection. The panel depicts a Christ crucified in front of an unknown church with a letter 'G'. After summarizing Defoer's study on the Utrecht and Greenville panels, the author will present the panel as Santa Croce in Gerusalemme, the last station to perform the virtual pilgrimage to Rome. The discussion will be followed by stylistic analysis to suggest that the three panels were made by different members from the same workshop in the early-sixteenth Southern Netherlands
Drivers of land use change and household determinants of sustainability in smallholder farming systems of Eastern Uganda
No full textSmallholder farming systems in sub-Saharan Africa have undergone changes in land use, productivity and sustainability. Understanding of the drivers that have led to changes in land use in these systems and factors that influence the systems’ sustainability is useful to guide appropriate targeting of intervention strategies for improvement. We studied low input Teso farming systems in eastern Uganda from 1960 to 2001 in a place-based analysis combined with a comparative analysis of similar low input systems in southern Mali. This study showed that policy-institutional factors next to population growth have driven land use changes in the Teso systems, and that nutrient balances of farm households are useful indicators to identify their sustainability. During the period of analysis, the fraction of land under cultivation increased from 46 to 78%, and communal grazing lands nearly completely disappeared. Cropping diversified over time; cassava overtook cotton and millet in importance, and rice emerged as an alternative cash crop. Impacts of political instability, such as the collapse of cotton marketing and land management institutions, of communal labour arrangements and aggravation of cattle rustling were linked to the changes. Crop productivity in the farming systems is poor and nutrient balances differed between farm types. Balances of N, P and K were all positive for larger farms (LF) that had more cattle and derived a larger proportion of their income from off-farm activities, whereas on the medium farms (MF), small farms with cattle (SF1) and without cattle (SF2) balances were mostly negative. Sustainability of the farming system is driven by livestock, crop production, labour and access to off-farm income. Building private public partnerships around market-oriented crops can be an entry point for encouraging investment in use of external nutrient inputs to boost productivity in such African farming systems. However, intervention strategies should recognise the diversity and heterogeneity between farms to ensure efficient use of these external inputs
Using farmer knowledge to combat low productive spots in rice fields of a Sahelian irrigation scheme
No full textIn the oldest sections of Burkina Faso's largest irrigation scheme in the Sourou Valley (13degrees 10'N, 03degrees 30'W) rice (Oryza sativa L.) yields dropped from about 5 to 6 t ha(-1) in the early 1990s, shortly after establishment of the scheme, to 2 to 4 t ha(-1) from 1995 onwards. Farmers blamed this yield decline on the appearance of 2 to 20 m diameter low productive spots. According to farmers and field measurements, the low productive spots decreased yields by 25-50 per cent. The low productive spots are caused by Zn deficiency. Low Zn availability is related to the very low DTPA-extractable Zn content of the soil (0-08-0.46 mg kg(-1)), the alkaline-calcareous character of the soil, the non-application of Zn fertilizers, and a relatively large P fertilizer dose (21 kg P ha(-1)). Farmers were correct in relating the calcareous nature of the soil to the presence of the low productive spots. They were instrumental in identifying application of decomposed organic resources (e.g. rice straw at 5 t ha(-1)) as a short-term solution that increases yields by 1.5 to 2.0 t ha(-1). Application of Zn fertilizer (10 kg Zn ha(-1)) in 29 fanner fields in the 2001 dry season eradicated the low productive spots and increased yields from 3.4 to 6.0 t ha(-1). Although application of Zn fertilizer is strongly recommended, it is not yet available in Burkina Faso. Based on a comparison of fertilizer prices on the world market and the local market, we expect that the use of Zn fertilizers will be highly profitable (cost/value ratiomuch greater than2). Despite the relatively recent introduction of irrigated rice cropping, most farmers showed a good understanding of cropping constraints and possible solutions. Both farmers and researchers mutually benefited from each other's knowledge and observations. Copyright (C) 2004 John Wiley Sons, Ltd
Collaborative Active Learning Method (CALM): A Case Study of USIU Post Graduate Course
No full textAccording to Cooperstein and Kocevar-Weidinger (2003), constructivist learning moves from experience to knowledge. Prince (2003) differentiates traditional learning with four common forms of effective learning and several studies have focused on active learning (Paulson and Foust, 1998; Mascarenhas, 1991; Aison, 2010; and Carlson and Winquist; 2011); and effective learning approaches (FAO, 1991; Defoer, 2009; Shen, Wu, Achhpiliya, Bieber and Hiltz, 2004).
This presentation assess effectiveness of collaborative active learning method under development for a research methods course premised on three key activities; assessment of effectiveness of cooperative learning; review of incremental learning; and evaluation of participatory learning experiences by collecting feedback from participating students. The analysis will constitute both simple descriptive research design and qualitative assessment.
Student’s group research project is the basis for learning concepts. Students assess extent to which the university is achieving its learning outcomes by collecting data from first year experience and capstone classes through triangulation of both quantitative and qualitative methods. Their research design approaches and rationale become the basis for class discussion of various research methods and presentation at end of semester. Presentation to involve discussion of similar methods by participants
Strengthening understanding and perceptions of mineral fertilizer use among smallholder farmers: evidence from collective trials in western Kenya
No full textIt is widely recognized that mineral fertilizers must play an important part in improving agricultural productivity in western Kenyan farming systems. This paper suggests that for this goal to be realized, farmers’ knowledge must be strengthened to improve their understanding of fertilizers and their use. We analyzed smallholder knowledge of fertilizers and nutrient management, and draw practical lessons from empirical collective fertilizer-response experiments. Data were gathered from the collective fertilizer-response trials, through focus group discussions, by participant observation, and via in-depth interviews representing 40 households. The collective trials showed that the application of nitrogen (N) or phosphorous (P) alone was insufficient to enhance yields in the study area. The response to P on the trial plots was mainly influenced by incidences of the parasitic Striga weed, by spatial variability or gradients in soil fertility of the experimental plots, and by interactions with N levels. These results inspired farmer to design and conduct experiments to compare crop performance with and without fertilizer, and between types of fertilizers, or responses on different soils. Participating farmers were able to differentiate types of fertilizer, and understood rates of application and the roles of respective fertilizers in nutrient supply. However, notions were broadly generated by unsteady yield responses when fertilizers were used across different fertility gradients, association with high cost (especially if recommended rates were to be applied), association of fertilizer use with hybrids and certain crops, historical factors, among other main aspects. We identified that strengthening fertilizer knowledge must be tailored within existing, albeit imperfect, systems of crop and animal husbandry. Farmers’ perceptions cannot be changed by promoting more fertilizer use alone, but may require a more basic approach that, for example, encourages farmer experimentation and practices to enhance soil properties such as carbon build-up in impoverished local soils
Exploring new pathways for innovative soil fertility management in Kenya
No full textAvailable from British Library Document Supply Centre-DSC:5359.2826(no 25) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
Accounting for environmental and socioeconomic sustainability in Northeast Thailand: towards decision support for farmers and extension workers
No full textSustainable agricultureFarming systemsFertilizersEconomic aspectsIncome
