Morphology of deoxyribonucleic acid extracted from cores of vaccinia virus

It has been shown recently that the outer layers of vaccinia virions can be removed selectively under mild conditions to yield a preparation that consists entirely of "cores" (K. B. Easterbrook, Ultrastruct. Res. 14:484, 1966). Since these cores can be very easily ruptured and dissolved, they would seem to offer advantages over complete virions as starting material for the extraction of unbroken genomes. This note describes results obtained in an investigation into the morphology of DNA isolated from vaccinia viral cores by further detergent treatment

African studies libraries: background to U.S. organization and initiatives and prospects for international cooperative projects : paper delivered at the German – North American resources project conference, 5 – 7 October 2006 ; [Vortrag am 6th Frankfurt scientific symposium, GNARP und wie sie die Welt sieht: Aussichten transatlantischer Partnerschaft im digitalen Zeitalter: 5.10.2006 - 7.10.2006]

The paper will provide a brief background to the history of the organization and cooperative efforts of African studies librarians in the United States including their efforts at international cooperation. Particular emphasis will be placed on the current opportunities for improved cooperation as digitization activities increase. Examples will include the DISA and Aluka initiatives and well as the Timbuktu manuscript digitization project at the Center for Research Libraries. Particular emphasis will placed on the possibilities for German-North American cooperation in the area of digital projects of historical photographs given the extensive collections held at Northwestern and Frankfurt

Everything You Know About the Bush Environmental Record is Wrong

Conventional wisdom says that George W. Bush has 'declared war on the environment.' Yet actual instances of Bush anti-environmental policies are few, while the new president has received no credit for significant actions to reduce air pollution. What's the political and media dynamic that makes everyone feel so sure that Bush is anti-environment?

Ferritin in the fungus Phycomyces

The iron-protein ferritin has been purified from mycelium, sporangiophores, and spores of the fungus Phycomyces blakesleeanus. It has a protein-to-iron ratio of 5, a sedimentation coefficient of 55S, a buoyant density in CsCl of 1.82 g/cm3, and the characteristic morphology of ferritin in the electron microscope. Apoferritin prepared from Phycomyces ferritin has a sedimentation coefficient of 18S and consists of subunits of molecular weight 25,000. In the cytoplasm of Phycomyces, ferritin is located on the surface of lipid droplets (0.5–2.0 µ in diameter) where it forms crystalline monolayers which are conspicuous in electron micrographs of sporangiophore thin-sections. Ferritin is found in all developmental stages of Phycomyces but is concentrated in spores. The level of ferritin iron is regulated by the iron level in the growth medium, a 50-fold increase occurring on iron-supplemented medium

A taxonomy of asymmetric requirements aspects

The early aspects community has received increasing attention among researchers and practitioners, and has grown a set of meaningful terminology and concepts in recent years, including the notion of requirements aspects. Aspects at the requirements level present stakeholder concerns that crosscut the problem domain, with the potential for a broad impact on questions of scoping, prioritization, and architectural design. Although many existing requirements engineering approaches advocate and advertise an integral support of early aspects analysis, one challenge is that the notion of a requirements aspect is not yet well established to efficaciously serve the community. Instead of defining the term once and for all in a normally arduous and unproductive conceptual unification stage, we present a preliminary taxonomy based on the literature survey to show the different features of an asymmetric requirements aspect. Existing approaches that handle requirements aspects are compared and classified according to the proposed taxonomy. In addition,we study crosscutting security requirements to exemplify the taxonomy's use, substantiate its value, and explore its future directions

Elicitation of requirements from multiple perspectives

Imperial Users onl