164,771 research outputs found
Using twins and scaling to construct cospectral graphs for the normalized Laplacian
The spectrum of the normalized Laplacian matrix cannot determine the number
of edges in a graph, however finding constructions of cospectral graphs with
differing number of edges has been elusive. In this paper we use basic
properties of twins and scaling to show how to construct such graphs. We also
give examples of families of graphs which are cospectral with a subgraph for
the normalized Laplacian matrix
Review of 'The politics of EU accession: ideology, party strategy and the European question in Hungary', by A. Batory
No abstract available
Expertise and Service: A Call to Action
Although theological librarianship occurs most often at seminaries or graduate level theology programs, there are also librarians working with theology on an undergraduate level. In many cases, these librarians are responsible for additional subject areas and may or may not have any theological expertise or training. While the two groups do the same types of work, they are doing so in different ways. To explore these commonalities and differences, a study was conducted among undergraduate theology liaisons and those results were compared with the literature and data regarding graduate level theological librarianship. One hundred ten undergraduate librarians responded to a survey regarding theological liaison activities, and the results indicate both the need for more research and the need for further emphasis on undergraduate subject-area liaison duties in theology and adjacent areas
Evolving Political Accountability in Kenya
published or submitted for publicationnot peer reviewe
Pipeline politics and energy (in)security in Central and South-Eastern Europe
No abstract available
Artemisinin: From Chinese Herbal Medicine to Modern Chemotherapy
Malaria is a disease that has blighted humankind since early times. The first antimalarial treatment available to Europeans was the dried bark of the cinchona tree from Peru. The main problem in its use was adulteration by other material. The ‘active principle’ was first extracted in 1820 and named quinine. It was found to be a more powerful and reliable drug than cinchona bark. Once its chemical structure had been determined, it was possible to synthesize substances chemically related to quinine that were equally powerful but could be manufactured industrially. Mepacrine (atabrine) was amongst the most successful, but had adverse side effects. To avoid these side effects, further chemical modification gave chloroquine, a highly successful drug. This sequence is a common way of converting an herbal remedy into a modern-style chemical drug. It parallels, to some extent, the process of potentiation common in traditional herbal medicine. By the 1970s, drug resistance had developed with chloroquine. To find and develop a new antimalarial drug that worked on an entirely different pharmacological principle, Chinese scientists turned to their herbal compendia (ben cao) and found that Artemisia annua (qing hao) was frequently mentioned as a treatment for intermittent fever. Whether, in view of the distinctive doctrines of Chinese medicine, it should be possible to extract an active principle as described above is discussed. After a very careful reading of the procedure given for the use of qing hao, an active substance, artemisinin, was extracted. Artemisinin has a truly remarkable chemical structure, and chemical modification produced artesunate, the drug of choice. To prevent the development of resistance, artesunate is used in combination with other antimalarial drugs. Modern pharmacology has largely ignored that other substances in artemisia and the cinchona bark may contribute to their therapeutic effect. This matter is also discussed
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