Systems of Parameters and the Cohen-Macaulay Property

Let $R$ be a commutative, Noetherian, local ring and $M$ an $R$-module. Consider the module of homomorphisms $\operatorname{Hom}_R(R/\mathfrak{a},M/\mathfrak{b} M)$ where $\mathfrak{b}\subseteq\mathfrak{a}$ are parameter ideals of $M$. When $M=R$ and $R$ is Cohen-Macaulay, Rees showed that this module of homomorphisms is always isomorphic to $R/\mathfrak{a}$, and in particular, a free module over $R/\mathfrak{a}$ of rank one. In this work, we study the structure of such modules of homomorphisms for general $M$

Quantifying Nitric Oxide Production in Platelets using a Griess Reagent System

Nitric oxide (NO) is a signaling molecule that regulates many physiological processes in the human body. Common examples of processes that NO is involved in range from immune responses to the regulation of blood pressure. In intact blood vessels, nitric oxide is constitutively released by vascular endothelial cells in order to prevent platelet adhesion and clot formation. Platelets have also been shown to release small amounts of NO as they aggregate on damaged blood vessels. Platelet-derived NO is hypothesized to play an important role in limiting the extent of clot formation. Although platelets produce nitric oxide during aggregation, it is difficult to accurately measure the concentration of nitric oxide that is released. The Griess reagent system is commonly used with other cell types and in other in vitro assays to measure NO production. Here, we used a commercially available Griess reagent kit (Cayman Chemical, Ann Arbor Michigan) to determine if the Griess reagent system could quantify nitric oxide production by aggregating platelets. Platelets were stimulated by common physiological agonists, including ADP, epinephrine, arachidonic acid, and collagen, and platelet NO production was quantified according to the manufacturer’s instructions. We found that arachidonic acid was the strongest agonist and epinephrine to be the weakest. The Cayman Chemical kit we used did not quantify nitric oxide production as we had previously hypothesized and led us to conclude that the kit should not be used for clinical purposes

Bromeliads as a Breeding Site for the Dengue Vector Aedes aegypti

Dengue Fever is a major public health concern in tropical and subtropical climates worldwide, including the city of Cairns, Australia, which is currently suffering a severe outbreak. The most important vector of the Dengue virus is the predominantly urban mosquito Aedes aegypti (L.), which lays its eggs in both artificial and natural containers, including the ornamental bromeliad plants found in many household gardens. The ability of larvae to develop to adulthood inside bromeliads has become controversial, however, and bromeliad enthusiasts frequently refuse to have their plants treated with insecticide. The aim of this study was to determine the conditions under which bromeliads can provide a suitable breeding site for Ae. aegypti. A total of 110 larvae were implanted in seven bromeliads and four artificial container controls, and rates of larval mortality and successful adult emergence were compared. Adult mosquitoes emerged from four out of seven bromeliads, and although larval death rates were high overall, there was no significant difference in productivity or mortality between bromeliad and control populations. These results have important implications for the management of Ae. aegypti breeding sites, which is currently the most promising method for curtailing the spread of Dengue Fever

Half‐Space Multigroup Transport Theory

A method for solving various half‐space multigroup transport problems for the case of a symmetric transfer matrix is explained. This method is based on the full‐range completeness and orthogonality properties of the infinite‐medium eigenfunctions. First, the albedo problem is considered. A system of Fredholm integral equations is derived for the emergent distribution of the albedo problem, and it is shown that this system has a unique solution. Then, by using the full‐range eigenfunction completeness, the inside angular distribution is obtained from the emergent distribution. Finally, the Milne problem and the half‐space Green's function problem are solved in terms of the emergent distribution of the albedo problem and the infinite‐medium eigenfunctions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69668/2/JMAPAQ-10-12-2220-1.pd