Fuse-holder concept expedites electronic component changes

Mounting circuit components in fuse holders facilitates component changing and extends component life with an estimated fifty percent saving of breadboard test time. Glass sleeves of the fuse holders allow easy component identification

The Moonlight Sonata

Non-fiction by Judy Winslo

Design of Geometric Molecular Bonds

An example of a nonspecific molecular bond is the affinity of any positive charge for any negative charge (like-unlike), or of nonpolar material for itself when in aqueous solution (like-like). This contrasts specific bonds such as the affinity of the DNA base A for T, but not for C, G, or another A. Recent experimental breakthroughs in DNA nanotechnology demonstrate that a particular nonspecific like-like bond ("blunt-end DNA stacking" that occurs between the ends of any pair of DNA double-helices) can be used to create specific "macrobonds" by careful geometric arrangement of many nonspecific blunt ends, motivating the need for sets of macrobonds that are orthogonal: two macrobonds not intended to bind should have relatively low binding strength, even when misaligned. To address this need, we introduce geometric orthogonal codes that abstractly model the engineered DNA macrobonds as two-dimensional binary codewords. While motivated by completely different applications, geometric orthogonal codes share similar features to the optical orthogonal codes studied by Chung, Salehi, and Wei. The main technical difference is the importance of 2D geometry in defining codeword orthogonality.Comment: Accepted to appear in IEEE Transactions on Molecular, Biological, and Multi-Scale Communication

Editorial: China’s impacts on Africa’s development

Much has been made of China’s economic ascendency in Africa, most notably its overtaking of the US in 2009 to become the continent’s largest trading partner. Beyond trade, the broader contours of Chinese loans, export credits, investment, and aid have changed Africa’s economic landscape since 2000 when the first Forum on China-Africa Cooperation (FOCAC) meetings were held. In the extensive discussions – in government meetings, the media, public fora, and academic settings – that have ensued, China has been portrayed in distinctly contrasting terms; on the one hand, as a responsible partner of the global south, creating new markets for African products and supplying affordable goods to African consumers, while on the other as a rapacious superpower plundering the continent’s resources and flooding its markets with cheap manufactures that further undermine local production. Consequently, the impacts of China on African economies and Africa’s development have become one of the most controversial topics in the wider and rapidly expanding field of Sino-African relations

Coded photographic proof paper could serve as convenient densitometer

Standard print-out proofing paper, preprinted with an identifying code, serves as convenient densitometer. Exposure to light darkens the paper and gives a measure of the density of the resultant photographic image or the total amount of exposure sustained by the paper