Student Financial Aid:The Roles of Loans and Grants (Working Paper 37)

This paper addresses the roles of loans and grants as forms of student financial aid. It begins with a simple choice model where individuals decide to pursue post-secondary studies if i) the net benefits of doing so are positive and ii) no financing or liquidity constraints stand in their way. The effects of loans and grants on these two elements of the schooling decision are then discussed. It is argued that based on equity, efficiency, and fiscal considerations, loans are generally best suited for helping those who want to go but face financing constraints, whereas grants are more appropriate for increasing the incentives for individuals from disadvantaged backgrounds to further their studies. Loan subsidies, which make loans part-loan and part-grant, are also discussed, including how they might be used to address “debt aversion”. Given that subsidised loans have a grant (subsidy) element, while grants help overcome the credit constraints upon which loans are targeted, the paper then attempts to establish some general rules for providing loans, for subsidising the loans awarded, and for giving “pure” grants. It concludes with an application of these principles in the form of a recent proposal for reforming the student financial system in Canada. *

The roles of EFN-1 and seam cell V2 in the transmission of a stop cue for the posterior lateral microtubule in Caenorhabditis elegans

A functional nervous system requires the precise arrangement of all nerve cells and their neurites. To achieve this correct assembly, a myriad of molecular guidance cues works together to direct the outgrowth of neurites to their correct positions. The small nematode C. elegans provides the ideal model system to study the complex mechanisms of neurite guidance due to its relatively simple nervous system, composed of 302 neurons. I used two mechanosensory neurons, called the posterior lateral microtubule (PLM), to investigate the role of the ephrin and Eph receptor protein family in neurite termination in C. elegans. Activation of the C. elegans Eph receptor VAB-1 on the PLM growth cone is sufficient to cause PLM termination, but the identity and location of the activating ligand has not been established. In my thesis I investigated the ability of the ephrin ligand EFN-1 to activate VAB-1 to cause PLM termination when expressed on the same cell (in cis) and on opposing cells (in trans) to the receptor. I showed that EFN-1 is able to activate VAB-1 in cis and in trans to cause PLM termination. I also assessed the hypodermal seam cells as the source of the ephrin stop cue using fluorescently labelled and seam cell mutant transgenic worms. I found that although the PLM shows consistent termination on the seam cell V2 in wild type worms independent of PLM length, this process is not significantly disrupted in seam cell mutants. With this information I have created a new hypothesis that the PLM neurite is able the provide a positional cue for the developing seam cells, and have created a new transgenic strain which can be used to assess the impact of PLM and ALM cell ablation on seam cell position. My research is the first to demonstrate the ability of an ephrin ligand to activate its ephrin receptor in cis, and further research can investigate if this finding has in vivo applications.