Low temperature specific heat (LTSH) is a powerful tool to investigate the physical properties of bulk samples. For superconductivity, LTSH can probe the pairing state in superconductors and provides additional information under magnetic fields. In this thesis, I present comprehensive specific-heat studies of superconductivity in YNi2B2C, NbSe2, and CeRu2. (1) Single crystalline YNi2B2C was found to be superconducting at the superconducting transition temperature Tc ~ 13.77 K. The superconducting specific heat Ce(T) can be described by either the point-node or the two-gap model. (2) Single crystalline NbSe2 has a two-dimensional crystalline structure showing the Tc ~ 6.7 K and the anisotropy in the critical fields, Hc2¡æ/Hc2// ~3. We investigated the Ce(T) and the electronic specific heat £^(H) by the two-gap model. Obtained fitting parameters, such as gap values and the relative ratio of two gaps in both analyses (Ce(T) and £^(H)), are comparable meaning that the superconductivity of NbSe2 can be described by the two-gap scenario. (3) Finally, we studied the DC magnetic susceptibility and the specific heat of polycrystalline CeRu2 in different magnetic fields. In the bulk CeRu2, the amount of the possible impurity phase or nano-clusters was reduced after annealing. Based on the analysis results of zero-field and in-field specific heat, CeRu2 is a BCS-like superconductor with an anisotropic gap.

For decades the question regarding foreign aid’s effectiveness has been disputed. The ongoing debate concerning whether foreign aid yields or prevents economic growth has been discussed by different scholars, though with dissimilar outcomes. Foreign aid is often criticized for creating destruction rather than stimulating developing countries economic growth, though the fundamentals for aid is to create opportunities for developing countries to evolve and gain better socio-economic structures. Different forms of aid are supposed to create different outcomes, i.e. short- and medium-term aid ought to stimulate the country while long-term aid such as infrastructure and education should create growth for the recipient country. The problem of aid is mostly corruption, corrupted regimes hinders the natural development for aid that is to say it hampers the positive outcome aid can produce. So, does foreign aid have a positive impact on recipient countries growth? The aim of this study is to acknowledge the importance of foreign aid. In order to analyse whether foreign aid results in economic growth for developing countries in Sub-Saharan Africa, a crosssection regression analysis has been conducted. To sum up the results of this study foreign aid doesn’t have a significant effect on economic growth in the region Sub-Saharan Africa although other variables such as education and foreign direct investment has a significant effect on growth.