Selected article

An immune system is a collection of mechanisms within an organism that protects against infection by identifying and killing pathogens and tumor cells. It detects a wide variety of pathogens, such as viruses and parasitic worms and distinguishes them from the organism's normal cells and tissues. Detection is complicated as pathogens adapt and evolve new ways to successfully infect the host organism.

To survive this challenge, several mechanisms have evolved that recognize and neutralize pathogens. Even simple unicellular organisms such as bacteria possess enzyme systems that protect against viral infections. Other basic immune mechanisms evolved in ancient eukaryotes and remain in their modern descendants, such as plants, fish, reptiles, and insects. These mechanisms include antimicrobial peptides called defensins, pattern recognition receptors, and the complement system. More sophisticated mechanisms, however, developed relatively recently, with the evolution of vertebrates.

Selected picture

Systems engineering techniques are used in complex projects: from spacecrafts to chip design, from robotics to creating large software products to building bridges, Systems engineering uses a host of tools that include modeling & simulation, requirements analysis, and scheduling to manage complexity.

Selected Systems scientist

Herbert Alexander Simon (June 15, 1916 – February 9, 2001) was an American political scientist whose research ranged across the fields of cognitive psychology, computer science, public administration, economics, management, and philosophy of science and a professor, most notably, at Carnegie Mellon University.

Simon was not only a polymath, but a truly innovative thinker. He was among the founding fathers of several of today's most important scientific domains, including Artificial Intelligence, information processing, decision-making, problem-solving, attention economics, organization theory, complex systems, and computer simulation of scientific discovery. He coined the terms bounded rationality and satisficing, and was the first to analyze the architecture of complexity and to propose a preferential attachment mechanism to explain power law distributions.

WikiProjects

• Wikipedia:WikiProject Systems
• Wikipedia:WikiProject Science
• Wikipedia:WikiProject Philosophy
• Wikipedia:WikiProject History of Science

Did you know

• ...that systems art (picture) is an art movement from the 1960s influenced by systems theory, which reflects on natural systems, social systems and social signs of the art world itself?

• ...that a successful experimental system must be stable and reproducible enough for scientists to make sense of the system's behavior, but unpredictable enough that it can produce useful results?

• ... that the anthropologist, linguist, and cyberneticist Gregory Bateson most noted writings are Steps to an Ecology of Mind (1972) and Mind and Nature (1980).

• ... that a multi-agent system (MAS) is a system composed of multiple interacting intelligent agents, which can be used to solve problems which are impossible for monolithic system to solve.

• ... that the American systems scientist John Nelson Warfield found systems science to consist of a hierarchy of sciences.
  • Beginning at the base, with a science of description,
  • continuing vertically with a science of design,
  • then a science of complexity,
  • and next a science of action, called "Interactive management".

• ...that British Columbians will get a second chance to vote on replacing the winner-takes-all election system with a single-transferable-vote system?

• ... that self-organization is a process of attraction and repulsion in which the internal organization of a system, normally an open system, increases in complexity without being guided or managed by an outside source.

...Archive

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• Related fields: History of Ideas | History of Science | History of Technology | Philosophy of Science

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