Synthesis and Structural Studies of Calcium and Magnesium Phosphinate and Phosphonate Compounds

The work presented herein describes synthetic methodologies leading to the design of a wide array of magnesium and calcium based phosphinate and phosphonates with possible applications as bone scaffolding materials or additives to bone cements. The challenge to the chemistry of the alkaline earth phosphonate target compounds includes poor solubility of compounds, and poorly understood details on the control of the metal\u27s coordination environment. Hence, less is known on phosphonate based alkaline earth metal organic frameworks as compared to transition metal phosphonates. Factors governing the challenges in obtaining crystalline, well-defined magnesium and calcium solids lie in the large metal diameters, the absence of energetically available d-orbitals to direct metal geometry, as well as the overall weakness of the metal-ligand bonds. A significant part of this project was concerned with the development of suitable reaction conditions to obtain X-ray quality crystals of the reaction products to allow for structural elucidation of the novel compounds. Various methodologies to aid in crystal growth including hydrothermal methods and gel crystallization were employed. We have used phosphinate and phosphonate ligands with different number of phosphorus oxygen atoms as well as diphosphonates with different linker lengths to determine their effects on the overall structural features. An interesting correlation is observed between the dimensionality of products and the increasing number of donor oxygen atoms in the ligands as we progress from phosphinic acid to the phosphorous acids. As an example, monophosphinate ligand only yielded one-dimensional compounds, whereas the phosphonates crystallize as one and two-dimensional compounds, and the di- and triphosphonate based compounds display two or three-dimensional geometries. This thesis provides a selection of calcium and magnesium compounds with one-dimensional geometry, as represented in a calcium phosphinate to novel two-dimensional sheets of magnesium and pillared calcium phosphonates. The preparation of these novel compounds has led to the establishment of synthetic protocols that allow for the direct preparation of compounds with defined structural features

AN ASSESSMENT OF IMPACT AND ADAPTATION STRATEGIES TO CLIMATE CHANGE BY LOCAL INDIGENOUS FARMERS OF MICHIKA LOCAL GOVERNMENT AREA OF ADAMAWA STATE, NIGERIA

The aim of the study is to assess the impact and adaptation strategies to climate change by the local indigenous farmers in Michika Local government Area of Adamawa State, Nigeria. The data of this study were collected using a structured questionnaire survey to 369 local indigenous farmers from the 8 district of the study area. 21 years of rainfall and temperature data were also obtained from the Adamawa State Agricultural Development Programme, Michika. The data collected were analyzed using descriptive statistics in terms of tables, percentage, and trend analysis of rainfall and temperature. The rainfall and temperature trend for the study area showed an increasing trend. The respondents are aware of the impact of climate change, and as such, they mentioned loss of soil fertility (23%), low yields of crops (170%), ease spread of pest and disease (14%), and flood and erosion (13%). The local indigenous farmers employed adaptation strategies such as planting early maturing crops (26.2%), planting resistant crops to pest and drought (22.7%), mixed farming (23.3%), and the intensive use of fertilizer (17.8%). However, constraints towards adaptation according to the respondents includes the lack of adequate knowledge on how to cope with adaptation (16.2%), limited access to improve crop varieties (18.6%), high cost of fertilizers and other farm inputs (19.2%), and the lack of financial resources (17.8%). Chi-square was used to assess the association for the indigenous farmer’s level of awareness of climate change and socioeconomic variables (gender, age, education, qualification, and farming experience). Therefore, all the calculated values mentioned respectively is greater than the critical value (Table 5,6,7,8) at a significance level of 0.05. In addition, we reject Ho and accept H1. Hence, there is association between all the socio-economic variables and climate change in the study area

AN ASSESSMENT OF IMPACT AND ADAPTATION STRATEGIES TO CLIMATE CHANGE BY LOCAL INDIGENOUS FARMERS OF MICHIKA LOCAL GOVERNMENT AREA OF ADAMAWA STATE, NIGERIA

The aim of the study is to assess the impact and adaptation strategies to climate change by the local indigenous farmers in Michika Local government Area of Adamawa State, Nigeria. The data of this study were collected using a structured questionnaire survey to 369 local indigenous farmers from the 8 district of the study area. 21 years of rainfall and temperature data were also obtained from the Adamawa State Agricultural Development Programme, Michika. The data collected were analyzed using descriptive statistics in terms of tables, percentage, and trend analysis of rainfall and temperature. The rainfall and temperature trend for the study area showed an increasing trend. The respondents are aware of the impact of climate change, and as such, they mentioned loss of soil fertility (23%), low yields of crops (170%), ease spread of pest and disease (14%), and flood and erosion (13%). The local indigenous farmers employed adaptation strategies such as planting early maturing crops (26.2%), planting resistant crops to pest and drought (22.7%), mixed farming (23.3%), and the intensive use of fertilizer (17.8%). However, constraints towards adaptation according to the respondents includes the lack of adequate knowledge on how to cope with adaptation (16.2%), limited access to improve crop varieties (18.6%), high cost of fertilizers and other farm inputs (19.2%), and the lack of financial resources (17.8%). Chi-square was used to assess the association for the indigenous farmer’s level of awareness of climate change and socioeconomic variables (gender, age, education, qualification, and farming experience). Therefore, all the calculated values mentioned respectively is greater than the critical value (Table 5,6,7,8) at a significance level of 0.05. In addition, we reject Ho and accept H1. Hence, there is association between all the socio-economic variables and climate change in the study area