<p>This research investigated the nature, source and the spatial variation of the salinity of the water used for irrigation in the urban farming area of Philippi, which lies in the Cape Flats region of the Cape Town Metropolitan Area, South Africa. The irrigation water is mainly drawn from the Cape Flats aquifer, and pumped into ponds for eventual crop irrigation. Water samples were collected in summer and in winter from fifteen selected sites using standard water sampling procedures. Each site consisted of one borehole and one pond. The samples were routinely analyzed for salinity levels, and concentrations of major and minor ions. From the same boreholes and ponds, water was sampled in summer for isotope analysis to assess effects of evaporation on the water quality and salinity. Descriptive statistics were used to display the variation in range of specific ions in order to compare them with the recommended ranges. Geographical Information Systems analysis described the spatial distribution of the salinity across the study area, and hydrogeochemical analysis characterized the various waters and detected similarities between the water samples in the study area and other waters found in the Cape Flats region. In addition, the US salinity diagram classification of irrigation water developed by Richards (1954) was used to assess the current suitability of groundwater and pond water samples collected during the entire sampling period for irrigation activities. The research indicated that the concentrations of some ions such as chloride, nitrate, potassium and sodium exceeded in places in the study area, the target range values set by the Department of Water Affairs and Forestry (DWAF, 1996) and the Food and Agriculture Organization (Ayers and Westcot, 1985). It revealed that borehole and pond water were mostly brackish across the area regarding their total dissolved salts content, and fresh water was only found in the middle part of the study area. The research found that sea water does not intrude into the aquifer of the study area, and the accumulation of salts in groundwater and soil in the study area is mainly due to the agricultural activities and partially due to the natural movement of water through the geological formation of the Cape Flats region. The conceptual model of the occurrence of the salinization process supported these findings. From this investigation it is understood that the groundwater and pond water in the study area were generally suitable for irrigation purposes but they have to be used with caution as the vegetables are classified as sensitive and moderately sensitive to salt according to DWAF Irrigation water guidelines (1996). The quality of these waters was mainly affected by the land use activities.</p>

No description available.

The American alligator (Alligator mississippiensis) has been frequently studied in large reservoirs and coastal marshes. Large ontogenetic shifts in their diet and morphology have been linked with changes in habitat use, with adult males using deep, open water and juveniles and nesting females relying on vegetated marsh. In certain regions of the inland portion of the alligator’s range, these different aquatic habitats are represented by seasonal wetlands and riverine systems that are separated by a terrestrial matrix. Ontogenetic habitat shifts, therefore, would require overland movements between systems, which has important implications for conservation of the species. I tested several commonly used methods of surveying alligator populations to determine the most effective method of studying alligators in seasonal wetlands. I then used systematic trapping, nest surveys and radio telemetry to determine habitat use and overland movement rates by different sex and size classes. I found that seasonal wetlands provided nesting and nursery sites for these inland alligator populations, but that both juveniles undergoing an ontogenetic shift and nesting females move between the wetlands and riverine systems. Overland movements by alligators between the wetland and riverine habitats establish a level of functional connectivity between these aquatic ecosystems. I constructed a habitat suitability index of both the wetlands and the surrounding landscape to determine which patch and landscape characteristics were important to wetland use by alligators. I found that both descriptive wetland characteristics and the spatial relationships between wetlands were important predictors of alligator use. Overland movement was related to upland landuse as well as distance between aquatic habitats. Conserving a variety of wetland sizes and types within an intact upland matrix is critical to maintaining connectivity across the landscape. Furthermore, understanding how species may act as mobile links between ecosystems, particularly those with ontogenetic niche shifts, illustrates the importance of approaching conservation from a landscape perspective.

<p>Candidates’ attitudes towards various personnel selection methods get attention of organizational and work psychology specialists because of various reasons. The most important reason is that individuals’ attitudes towards personnel selection methods influence their latter behavior. Although there is a substantial amount of studies carried out in different countries, there is no data from Lithuanian and Swedish samples. The aim of current study was to analyze the attitudes towards personnel selection methods among Lithuanian students, Lithuanian employees and Swedish students. The participants (197 students and 86 employees) filled in a questionnaire, which includes short descriptions of 10 personnel selection methods as well as items about fairness of these methods. According to the results of the study, work-sample tests were ranked as the fairest personnel selection method in the Lithuanian sample. The fairest personnel selection methods in Swedish sample were work-sample tests, interview, resumes, and personal references. Lithuanian students ranked the fairness of written ability test and honesty test more favorably than Swedish students, but Swedish students tended to rank as more favorable interview, resumes, personal references and personal contacts. Personal contacts and graphology were ranked the lowest on fairness dimension in Lithuanian sample, and Swedes ranked only graphology as the least fair personnel selection method. Lithuanian employees ranked personal references, personal contacts and graphology more favorably than Lithuanian students. In Lithuanian students sample, perception of personnel selection method as a scientifically proved, logic and precise or providing an opportunity to show one’s skills, had the strongest connection with favorability ranking of personnel selection method’s fairness. In the Lithuanian employees and the Swedish students samples, perception of the method as logic or providing an opportunity to show one’s skills, had the strongest link with fairness.</p>

This thesis was aimed at the development of a Geographical Information System (GIS) based model to support the Rwanda Land Use and Development Master Plan. Developing sustainable land management is the main task of this master plan. Stakeholder’s involvement was of key importance. Their demands should be analysed and visualised to support discussions and the decision-making process. Spatial Multicriteria Decision Analysis (MCDA) is a proven method for land-use planning purposes. However, most land-use planning applications focus on a specific theme, such as urban development. In addition, land-use planning is often limited to a relatively small area. This thesis focused at the development of a countrywide GIS model, containing all land-uses accommodated in three main land-use categories: urban, agriculture and conservation. The GIS model was largely based on the Land-Use Conflict Identification Strategy (LUCIS) model. Many of the goals, objectives, and subobjectives that described the earlier mentioned land-use categories were adopted from the original model. However, a significant number of them were dropped, and new were created to suit the Rwandan situation. Stakeholder’s involvement was realized by assigning weights to the goals and preference maps. The Analytical Hierarchy Process (AHP) was used as weighting method. ESRI’s ArcGIS ModelBuilder was used to give the model shape in the GIS. Firstly, suitability maps were created of all elements in the model. The suitability maps were then transformed into preference maps by weighting them. In the next step the preference maps were collapsed in three classes: low, medium and high preference. Finally, the preference maps of the three land-use categories were combined, in order to visualize conflict areas. Ortho photos proved to be useful when acting as reference for the suitability and preference maps. Despite a large number of missing datasets, the GIS model was executed to simplify the understanding. However, many of the obtained results were unreliable because of the incompleteness of datasets, and can therefore not be used for decision-making.  Unfortunately, due to the stage of the project it was not possible to obtain weights from the stakeholders, and should therefore be done when the time is right. Right Choice DSS, a very user-friendly decision support application, was proposed to use for calculating weights. To conclude, the developed GIS model integrated countrywide land-use suitability mapping and stakeholders’ wishes that can be used for discussions and decision making.

Current transportation methods within the Central Arizona region revolve primarily around automobiles. In order for the region to become more economically resilient and environmentally sustainable, alternative transportation methods must be considered. One such alternative that has shown great promise in other regions of the United States is rail transport. Rail transport, including commuter rail or high speed rail, has proven to not only be an effective alternative to automobile transport, but also as a more environmentally sustainable transportation option. The I-11 Super Corridor study, a part of the University of Arizona’s Sustainable City Project 2014, applied next generation urban planning design ideas to the planned Interstate 11 corridor, a major transportation artery that will connect Mexico and Canada. This study inspired this project’s focus on the concept of identifying suitable routes for new transportation infrastructure within the central and southern Arizona regions. Through the incorporation of commuter or high speed rail within central and southern Arizona, a more resilient regional economy and environment can be created. The previous I-11 Super Corridor study presented the incorporation of different regional factors, including population density and economic statistics, to determine suitable routes for future transportation corridors. This project integrates the utilization of specific local and regional data and advanced GIS analysis to determine suitable routes for new rail transport corridors within Maricopa, Pinal and Pima Counties.

Candidates’ attitudes towards various personnel selection methods get attention of organizational and work psychology specialists because of various reasons. The most important reason is that individuals’ attitudes towards personnel selection methods influence their latter behavior. Although there is a substantial amount of studies carried out in different countries, there is no data from Lithuanian and Swedish samples. The aim of current study was to analyze the attitudes towards personnel selection methods among Lithuanian students, Lithuanian employees and Swedish students. The participants (197 students and 86 employees) filled in a questionnaire, which includes short descriptions of 10 personnel selection methods as well as items about fairness of these methods. According to the results of the study, work-sample tests were ranked as the fairest personnel selection method in the Lithuanian sample. The fairest personnel selection methods in Swedish sample were work-sample tests, interview, resumes, and personal references. Lithuanian students ranked the fairness of written ability test and honesty test more favorably than Swedish students, but Swedish students tended to rank as more favorable interview, resumes, personal references and personal contacts. Personal contacts and graphology were ranked the lowest on fairness dimension in Lithuanian sample, and Swedes ranked only graphology as the least fair personnel selection method. Lithuanian employees ranked personal references, personal contacts and graphology more favorably than Lithuanian students. In Lithuanian students sample, perception of personnel selection method as a scientifically proved, logic and precise or providing an opportunity to show one’s skills, had the strongest connection with favorability ranking of personnel selection method’s fairness. In the Lithuanian employees and the Swedish students samples, perception of the method as logic or providing an opportunity to show one’s skills, had the strongest link with fairness.

No description available.

<p>This research investigated the nature, source and the spatial variation of the salinity of the water used for irrigation in the urban farming area of Philippi, which lies in the Cape Flats region of the Cape Town Metropolitan Area, South Africa. The irrigation water is mainly drawn from the Cape Flats aquifer, and pumped into ponds for eventual crop irrigation. Water samples were collected in summer and in winter from fifteen selected sites using standard water sampling procedures. Each site consisted of one borehole and one pond. The samples were routinely analyzed for salinity levels, and concentrations of major and minor ions. From the same boreholes and ponds, water was sampled in summer for isotope analysis to assess effects of evaporation on the water quality and salinity. Descriptive statistics were used to display the variation in range of specific ions in order to compare them with the recommended ranges. Geographical Information Systems analysis described the spatial distribution of the salinity across the study area, and hydrogeochemical analysis characterized the various waters and detected similarities between the water samples in the study area and other waters found in the Cape Flats region. In addition, the US salinity diagram classification of irrigation water developed by Richards (1954) was used to assess the current suitability of groundwater and pond water samples collected during the entire sampling period for irrigation activities. The research indicated that the concentrations of some ions such as chloride, nitrate, potassium and sodium exceeded in places in the study area, the target range values set by the Department of Water Affairs and Forestry (DWAF, 1996) and the Food and Agriculture Organization (Ayers and Westcot, 1985). It revealed that borehole and pond water were mostly brackish across the area regarding their total dissolved salts content, and fresh water was only found in the middle part of the study area. The research found that sea water does not intrude into the aquifer of the study area, and the accumulation of salts in groundwater and soil in the study area is mainly due to the agricultural activities and partially due to the natural movement of water through the geological formation of the Cape Flats region. The conceptual model of the occurrence of the salinization process supported these findings. From this investigation it is understood that the groundwater and pond water in the study area were generally suitable for irrigation purposes but they have to be used with caution as the vegetables are classified as sensitive and moderately sensitive to salt according to DWAF Irrigation water guidelines (1996). The quality of these waters was mainly affected by the land use activities.</p>

The larger grain borer (LGB) Prostephanus truncatus (Horn) is the most important pest of farm stored maize and cassava in Africa. This alien invasive species was introduced into the continent from Mesoamerica in the late 1970s and by 2008 had spread to at least 18 countries. In contrast to indigenous primary storage pests, LGB exists as on-farm and as wild populations, hence, sustainable control must target both environments. Biological control is especially attractive for wild populations to reduce early season grain store infestation, while cultural and chemical methods are useful to protect stored produce directly. Two populations of the predator Teretrius nigrescens Lewis were introduced into several African countries' as a biocontrol agent. It has shown long-term success and cost effective control in warm-humid areas. Control has however not been successful in cool and hot-dry zones. The aim of this study was to investigate the possible underlying genetic and ecological explanations for these observations and the possibility of joint use of molecular markers and ecological parameters in the development of sustainable control strategies. A 28-month baseline monitoring and recovery activity was done in from 2004 in five regions in Kenya along an east-westerly transect. Monitoring and live sample collection was also done in the original outbreak area in eastern Kenya. There was greater LGB flight activity in western Kenya (high potential maize production area) than the low potential areas. Very few T. nigrescens were recovered, solely in the eastern regions. LGB flight activity followed a seasonal pattern mostly related to changes in the relative humidity at 12:00, rainfall and dew point temperature but with a 3 - 4 week lag. A linear predictive model based on these factors predicted 27 % of the observed flight activity. The survival and predation of five strains of T. nigrescens were compared at eight temperature levels between 15 °C and 36 °C at low and high humidity. All the strains of T. nigrescens exerted a significant reduction of LGB population build-up between 21 °C and 33 °C with generally better performance under humid conditions. There was no evidence of T. nigrescens development at 15 °C. At 18 °C, T. nigrescens oviposition and development was observed but the effect on LGB did not differ significantly from the control. The KARI population was the least effective in preventing grain damage at lower temperatures, but performed better than other strains above 30 °C at low humidity conditions. There was no control at 18 °C and 36 °C under both high and low humidity conditions. Since the extent of genetic differentiation in T. nigrescens was unclear from prior studies, several molecular marker techniques were progressively used. The RAPD-PCR did not reveal any genetic diversity between geographical populations. A 1000bp region of the mitochondrial mtCOI gene revealed two distinct clades differing consistently at 26 segregating sites. The two clades can be identified by simple PCR-RFLP procedure using single or double sequential restriction with EcoR1, HincII, RsaI and DdeI digestion. However, the two lineages co-exist among the mid-altitude Central American populations. The internal transcribed spacer regions ITS1 and ITS2 with some neighbouring coding sequences of the ribosomal DNA were cloned and sequenced. The spacer regions were so variable in length and sequence between T. nigrescens and related Histeridae species that direct sequence alignment was not meaningful. Within T. nigrescens, there was intragenomic variability of the spacer regions mostly involving insertions and deletions of variable tandem repeat units predominantly within the ITS regions. The short flanking coding (18S, 5.8S and 21S) regions were conserved across populations and six other Histeridae species. There was no significant secondary structure variation of the ITS regions among populations of T. nigrescens. Twenty-four novel variable microsatellite markers were developed and tested on the Honduras populations. Alleles per locus ranged between two and twelve with observed heterozygosity between 0.048 and 0.646. Six loci deviated significantly from Hardy Weinberg Equilibrium and possibly had null alleles. The success of microsatellite amplification in outgroup species and variability of markers declined with an increase in the phylogenetic distance between the test species and T. nigrescens. Genotyping 432 individuals from 13 geographic populations revealed a comparatively higher genetic diversity in field populations. Partial isolation by distance and time was observed. Population bottlenecks were not detected, but recent expansion was evident in laboratory populations. Although five dominant genetic clusters were identified by Bayesian methods, meaningful hierarchical population structure was observed at between two and nine population groups (p < 0.01; 10,000 iterations). Biological control of the larger grain borer using T. nigrescens seems an important aspect of the sustainable integrated control approach of the pest. Ecological adaptations, appropriate release strategies and genetic diversity are all essential considerations in these efforts and could be responsible for the variable success already observed. There is some genetic differentiation between populations of T. nigrescens but, further studies would be necessary to ascertain the contribution of such diversity to its predatory performance. The effect of laboratory culturing in aggravating genetic drift should be accommodated to avoid loss of diversity during sampling, quarantine, rearing and release of the predator. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2009.