Once Again Caligula Illness

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When Protest Doesn\u27t Quite Fit the Mold

White people protesting is powerful. It is a privilege to be guaranteed that someone will listen to us, as pointed out by Jerome Clarke in a piece about last year’s “Won’t Stand For Hate” protest. With that privilege comes a responsibility that has been neglected on this campus. I agree with the students who protested on the steps of Penn Hall and spoke out during the Student Senate meeting about the way our administration is handling the mold situation in Hanson Hall. The response was insufficient and it directly contradicts the College’s verbal commitment to promoting a healthy living and learning environment. However, as I walked by the students protesting on Friday, I was hit with irony and felt ashamed of the way many of us have responded to this issue. Perhaps I wouldn’t feel that way if every issue facing the students of this campus, specifically those most marginalized, were met with similar outcry from the majority population here. [excerpt

Entrepreneurship in the Informal Economy of Latin America and the Caribbean: A conceptual model of the finance-performance nexus

Although the size of the informal economy is relatively large across Latin America and the Caribbean, it is not completely understood how deficiencies in the institutional environment may be related either to the propensity for entrepreneurship or the performance of entrepreneurs in the informal economy. Focusing on institutional heterogeneity, this paper characterizes external finance (i.e. local family-based equity, remittances, bank credit, business angel finance and venture capital) in terms of (1) the mix of finance, business consulting and contacts, (2) governance mechanisms (i.e. reputational capital versus formal contracts) and (3) fungibility (i.e. discretion to use funds borrowed or received for alternative purposes); and develop a number of propositions. The outcome is a finance-performance nexus that provides a basis for a theoretically grounded empirical investigation of the relationship between the financial aspects of the institutional environment and both the propensity for entrepreneurship and the performance of entrepreneurs in the informal economy

Polyamine regulation of nitric oxide production in LPS-activated macrophages

© European Communities, 1999 Reproduction is authorised provided the source is acknowledgedPolyamines are physiological cellular constituents essential for cell growth and differentiation, and regulate a multitude of cellular functions (1-4). Nitric oxide (NO) is an effector molecule in both the cardiovascular and nervous systems (5,6). Intracellularly, NO and polyamines are derived from arginine, the latter via the rate-limiting enzyme ornithine decarboxylase (ODC; 7). This enzyme, like the inducible nitric oxide synthase (iNOS), is induced by proinflammatory cytokines and bacterial lipopolysaccharide (LPS), resulting in enhanced enzyme activity and increased polyamine biosynthesis (8,9). While the increase in polyamine synthesis would have important implications for cell growth and proliferation, it is not clear how this might affect iNOS pathway. Inhibition of polyamine biosynthesis impairs the phagocytic capacity of macrophages (10) and can block macrophage activation by tumour necrosis factor (11). Recently, exogenous polyamines have been shown to inhibit NO production in LPS-activated J774 cells (12) and by isolated neuronal NO synthase (13). However, these effects required relatively high concentrations of polyamines compared to those found in plasma and in intact cells (14), and appear to be due to aldehyde metabolites resulting from polyamine oxidation by the amine oxidase present in calf serum (15-17). In this study we have explored the effects of both endogenous and exogenous polyamines on the inducible L-arginine-NO pathway by examining whether inhibition of ornithine decarboxylase (ODC) and thus of polyamine biosynthesis (7), regulates NO production in lipopolysaccharide-activated J774 cells, a murine macrophage cell lineFinal Published versio

Relaxing The Hamilton Jacobi Bellman Equation To Construct Inner And Outer Bounds On Reachable Sets

We consider the problem of overbounding and underbounding both the backward and forward reachable set for a given polynomial vector field, nonlinear in both state and input, with a given semialgebriac set of initial conditions and with inputs constrained pointwise to lie in a semialgebraic set. Specifically, we represent the forward reachable set using the value function which gives the optimal cost to go of an optimal control problems and if smooth satisfies the Hamilton-Jacobi- Bellman PDE. We then show that there exist polynomial upper and lower bounds to this value function and furthermore, these polynomial sub-value and super-value functions provide provable upper and lower bounds to the forward reachable set. Finally, by minimizing the distance between these sub-value and super-value functions in the L1-norm, we are able to construct inner and outer bounds for the reachable set and show numerically on several examples that for relatively small degree, the Hausdorff distance between these bounds is negligible