The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. The brain is located in the head, usually close to the sensory organs for senses such as vision. The brain is the most complex organ in a vertebrate's body. In a human, the cerebral cortex contains approximately 15–33 billion neurons, each connected by synapses to several thousand other neurons. These neurons communicate with one another by means of long protoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells.
Paul Erdős, in a standard greeting he would make when he was not contemplating some mathematical problem, as quoted in My Brain Is Open : The Mathematical Journeys of Paul Erdos (1998) by Bruce Schechter, p. 10
Want to know what the weather will be like tomorrow? A simple internet search will provide a forecast, or, more likely, many forecasts. How can you be sure which one is accurate? And what if you also want to know the pollen count because you are allergic, or pollution levels because you worry about your child's asthma? EU-funded researchers are answering those questions with an innovative online platform providing easy access to comprehensive, accurate, localised and personalised environmental and meteorological information.
EN 
CS
DE
ES
FR
HU
IT
PL
PT
РУ
SK
TR
УК
AR
中文
