In the semi-arid Limari­ River basin, Region of Coquimbo in northern Chile sixty percent of years receive less than the long-term average annual precipitation, and dry spells tend to be multi-year. Below-normal precipitation is not always associated with ENSO cycles, but shows a high correlation to El Nino 3 region sea surface temperature.Since early during the colonial period, land in Coquimbo was utilized as a source of minerals, meat, wheat, and timber for smelters. These extractive productive processes caused the destruction of most of the natural vegetation. Impacts of past use have persisted until today and the region is still affected by intense degradation. Land ownership was originally held in haciendas and communes. Analysis of Landsat satellite imagery shows that vegetation response increases marginally during rainy years in both land tenure regimes. Most of the increase is explained by the planting of rainfed wheat and the response of less palatable native species such as Gutierrezia spp. Hence, the capacity of natural vegetation to respond to above normal precipitation is limited on both private and communal lands.Twenty five percent of the land belongs to agricultural communes, and families in these communes are considered to be poor or indigent. Three agricultural communes were surveyed, and a vulnerability index was constructed based on the community right-holders' responses. Findings show that access to productive resources (i.e., land, water, technology, credit) is a key determinant of differential vulnerability. Vulnerability is defined here as the capacity of an individual or a community to adapt (or cope, or respond) to drought. Differences in access within communities are caused by the inequitable distribution of land by the communes' boards of directors in the recent past. Access to agricultural credit is limited because families do not have collateral. Vulnerability is also conditioned by access to water, greenhouses, irrigation technology, chemicals, and improved seed. The most vulnerable families depend on off-farm employment provided by private agriculture. Governmental responses are reactive based on emergency relief rather than proactive: there is no drought long-term planning, nor consideration of differential levels of vulnerability levels among different segments of the population.

Salinity has been shown to reduce vegetative growth, crop quality, and yield in agricultural crops. Remote sensing is capable of providing data about large areas. This project was designed to induce salinity stress in a crop, pak choi, and thereafter monitor the response of the crop as expressed by its spectral reflectances. The project was conducted in the National Taiwan University Phytotron, and spectral data was collected using a GER 2600. Yield and soil salinity (ECe) were also measured. After three seasons of data were collected, wavelengths sensitive to salinity were selected. These wavelengths, which are within the spectral response of biochemicals produced by plants as a response to soil salinity, were used to create two indices, the Salinity Stress Index (SSI) and the Normalized Salinity Stress Index (NSSI). After creating the indices tests were conducted to determine the efficacy of these indices in detecting salinity and drought stresses as compared to existing indices (SRVI and NDVI). This project induced salinity and drought stress in a crop, pak choi, and thereafter monitored the response of the crop as expressed by its spectral reflectances. The SSI and NSSI correlated well to both ECe and marketable yield. Additionally the SSI and NSSI were found to provide statistical differences between salinity stressed treatments and the control treatment. Drought stress was not detected well by any of the indices reviewed although the SSI and NSSI indices tended to increase with drought stress and decrease with salinity stress. As a final test, specific ion toxicities of sodium and chloride were tested against the developed indices (SSI and NSSI) and existing indices (NDVI, SRVI, and NDWI). There were no differences in SSI and NSSI responses to specific ion concentration in the high salinity treatments. These results indicated that the SSI and NSSI are not sensitive to the specific ion concentration in irrigation water. However, the SSI and NSSI were higher for the sodium water than the choride water in the low salinity treatments. It is likely that this difference was caused by the fact that the high SAR water decreased infiltration and caused water stress.

No description available.

No description available.

Climatic variability and change can have profound impacts on human societies and wildlife habitats. Extreme events and natural hazards such as floods, droughts, and windstorms, can lead to loss of lives, economic damages, and disruption in livelihoods, infrastructure, and ecosystems. These impacts depend on the intensity and the magnitude of the hazard and the characteristics of the society hit by the disaster. Investigating and predicting adverse effects of frequent climatic hazards are essential for policy makers and resource managers to plan for the future and be prepared for the consequences of these types of natural disasters. Vulnerability assessments provide a framework to detect the potential threats by exploring the nature of the hazard as well as the political, economic, and social conditions that are expected to affect the capacity of communities to cope with or adapt to that hazard. This research involves the development of a framework for vulnerability assessment of flood and drought at the river basin, sub-catchment, and community scale. The vulnerability assessment method is composed of three major components of exposure, sensitivity, and adaptive capacity. Several indicators are identified to represent these major components of the vulnerability structure. The developed vulnerability assessment has then been implemented on the Upper Ottawa River Basin, Canada. A Geographic Information System-based methodology is used to manage a wide variety of data, to aggregate and integrate several indicators including socio-economic and biophysical indicators, and to visualize the final vulnerability map. The studied areas are categorized in three levels of the vulnerability, high, moderate, and low. North Bay is identified as highly vulnerable to both flood and drought risk. Noranda is also classified as a highly flood-vulnerable area. The vulnerability assessment will provide a valuable insight for mitigation planning as well as prioritizing resource allocation for decision makers. In this research, the location and adequacy of the hydrometric monitoring stations in the Upper Ottawa River Basin are evaluated using the vulnerability map for optimum design of monitoring network.

Thesis (M.A. (Psychology))--North-West University, Potchefstroom Campus, 2008.

Thesis (M.A. (Psychology))--North-West University, Potchefstroom Campus, 2008.

No description available.

Desiccation effects on rate and pattern of protein synthesis in Brassica napus (cv westar) and Brassica juncea (cv cutlass) have been examined. Results showed that while the rate of water loss was similar in the two species, the inhibition of amino acid incorporation was greater in B. napus than B. juncea at any given level of desiccation. Electrolyte leakage increased with the degree of desiccation and was greater in B. napus than in B. juncea. In both, the increase in leakage was much sharper after 12 hours of desiccation. Quantitative changes in patterns of boiling-stable protein synthesis due to desiccation stress were observed. The control level of protein radioactivity which was boiling-stable in B. napus was 16.16% and 19.96% for B. juncea. After desiccation, the percentage of boiling-stable radioactivity increased to 23.30% for B. juncea and 16.63% for B. napus. In vitro translation of total RNA indicated that desiccation alone does not induce the synthesis of new mRNA species in either cultivar, but it may change the translation pattern resulting in different levels of abundance of proteins.

No description available.