Like many astronomy instructors this past autumn, I have been forced to teach my classes online. That means re-creating PowerPoint presentations, inasmuch as communicating visually on a small screen is different from doing so large one. In the process came see an old acquaintance in new way. Tycho’s supernova (left) imaged by Chandra X-Ray Observatory. (Courtesy of NASA/CXC/RIKEN & GSFC/T. Sato...

Organisms are machines designed by their evolution to play a certain role. This role, together with the environment within which it is played, is called the organism's niche 1. For example, most cats — tigers, leopards, mountain lions — play the role of solitary hunters; wolves and wild dogs are social hunters; antelope are social grazers; and so on. The niche defines the patterns of adaptive b...

The differences model, which argues that males and females are vastly different psychologically, dominates the popular media. Here, the author advances a very different view, the gender similarities hypothesis, which holds that males and females are similar on most, but not all, psychological variables. Results from a review of 46 meta-analyses support the gender similarities hypothesis. Gender...

A match sequence between two sentences of a language consists of similarities and di erences to represent simi lar parts and di ering parts between those sentences A translation example is a corresponding of two sentences in which one of them from the language L and the other one from the language L From given two translation examples we create a match sequence for sentences of the language L a...

Given a set S, we show that there is a strict relation between the notion of similarity on S and the one of fuzzy subgroup of transformations in S . Such a relation enables us to extablish a connection between fuzzy subgroups and distances.

Comparison of protein structures can reveal distant evolutionary relationships that would not be detected by sequence information alone. This helps to infer functional properties. In recent years, many methods for pairwise protein structure alignment have been proposed and are now available on the World Wide Web. Although these methods have made it possible to compare all available protein stru...