Tuesday, May 27, 2008

Homeodynamics

"HOMEODYNAMICS - One of the dominating motifs in biological thinking was provided by the physiologist Claude Bernard in Paris in the 1850s. Bernard, who among many other discoveries carried out some of the earliest systematic studies on what were later to become known as enzymes and hormones, saw living systems as explicable neither by vitalism (the belief that there existed some special 'life forces' beyond the reach of chemistry or physics) nor by mechanism. "He regarded stability as a major organising physiological principle, and emphasised the constancy of what he described as the milieu interieur - the 'internal environment' - of multicellular organisms, their tendency to work to regulate this environment in terms of temperature, acidity, ionic composition and so forth.

This capacity he saw as providing a stable context in which the individual cells of the body can function with a minimum of disruptive turmoil. "Seventy years later the American physiologist Walter Cannon generalzed Bernard's concept by introducing the term homeostasis - the tendency of a regulated system to maintain itself close to some fixed point, like the temperature of a room controlled by a central heating system and a thermostat. No modern textbook account of physiological or psychological mechanisms fails to locate itself within this homeostatic metaphor. But the metaphor of homeostasis contrains our view of living systems. "Lifelines are not purely homeostatic: they have a beginning at conception, and an end at death. Organisms, and indeed ecosystems, develop, mature and age.

The set oints of homeostatic theory are not themselves constant during this trajectory but change over time. The organism switches its own thermostat. Organisms are active players in their own fate, not simply the playthings of the gods, nature or the inevitable workings-out of replicator-driven natural selection. To understand lifelines, therefore, we need to replace homeostasis with a richer concept, that of homeodynamics."

Monday, May 19, 2008

Adaptive system

An adaptive system is a system that is able to adapt its behavior according to changes in its environment or in parts of the system itself. A human being, for instance, is certainly an adaptive system; so are organizations and families. Some man-made systems can be made adaptive as well; for instance, control systems utilize feedback loops in order to sense conditions in their environment and adapt accordingly. Robots incorporate many of these control systems. Neural Networks are a common type of algorithmic implementation of adaptive systems.

Diffusion of innovations theory can help to explain the uptake of new ideas, practices and products by individuals and social groups -- human adaptive systems.

Monday, May 12, 2008

Microsoft Reciprocal License (Ms-RL)

This Microsoft license allows for distribution of derived code so long as the modified source files are included and retain the Ms-RL. The Ms-RL allows those files in the distribution that do not contain code originally licensed under Ms-RL to be licensed according to the copyright holder's choosing. This is equivalent to the CDDL or LGPL (GPL with a typical "linking exception"). Initially known as the Microsoft Community License, it was renamed during the OSI approval process.

On December 9, 2005, the Ms-RL license was submitted to the Open Source Initiative for approval by John Cowan. OSI then contacted Microsoft and asked if they wanted OSI to proceed. Microsoft replied that they did not wish to be reactive and that they needed time to review such a decision.

At the O'Reilly Open Source Convention in July 2007, Bill Hilf, director of Microsoft's work with open source projects, announced that Microsoft had formally submitted Ms-PL and Ms-RL to OSI for approval. It was approved on October 12, 2007 along with the Ms-PL. According to the Free Software Foundation, it is a free software license. However, unlike the Microsoft Public License, it is not compatible with the GNU GPL.

Tuesday, May 06, 2008

Norse colonization of the Americas

Norse sailors, often referred to as Vikings, explored and settled areas of the North Atlantic, including the northeast fringes of North America, beginning in the 10th century. While this settlement process did not have the lasting effects that later settlements and conquests would have, it can be seen as a prelude to wide-scale European settlement in the Americas.

The Viking activities are often erroneously described as the Viking colonization of North America, but there are few findings to support the idea that the Vikings colonized North America, except for Greenland which they occupied for almost 500 years . Outside Greenland, though, the Viking settlements only grew to a small size and never fully developed into permanent colonies, partly because of hostile relations with Native Americans, whom the Norse referred to as Skr├Žlings. In turn, the Viking exploited the natural resources such as furs and lumber. Lumber, in particular, was in short supply in Norse Greenland, due to deforestation.