Nemesis, the goddess of revenge, punished Narcissus for not accepting the unrequited love of Echo. Nemesis caused him to fall in love with his own reflection he saw in a pool near the cave where Echo had died. Narcissus refused to leave the reflection of himself and, like Echo, starvation was going to claim him. But not before he cried out to his reflection: "Farewell, dear boy. Beloved in vain.". Echo's voice repeated "farewell" from the cave and Narcissus died by the bank of the pool.
After some time, Echo began to grow thin from starvation until her body withered away entirely into dust, leaving nothing but her voice. To this day Echo's voice still calls back from caves and labyrinths, repeating the last spoken words forever. And thus ends the story of echo and Narcissus.
Laplace's equation
Laplace's equation is a partial differential equation, of the second order. It is named after Pierre-Simon Laplace, an 18th century mathematician who first described it. One of the uses of the equation is to predict the conduction of heat, another to model the conduction of electricity.
Gene Tierney
Gene Eliza Tierney (November 19, 1920 - November 6, 1991) was an American actress. She was born in Brooklyn, New York City. She starred several movies including "Heaven Can Wait", "Laura", "Leave Her to Heaven", "The Razor's Edge", "The Ghost and Mrs. Muir", "Whirlpool", "The Mating Season" and "The Left Hand of God".
Tierney was born on 19 November 1920. She was born into a wealthy Brooklyn family. On a family vacation she toured the Warner Brothers studio and was spotted by director Anatole Litvak. After a screen test she was offered a contract. But her father disapproved of her becoming a Hollywood actress. He finally approved of her acting on the Broadway stage if she would first make her society debut. She played several bit parts before again being noticed by Hollywood. She had a brief contract with Columbia Pictures but returned to Broadway. Her first break was in the play "The Male Animal" as a college cheerleader. This time 20th Century Fox wanted to sign her to a contract. They allowed her creative control over her parts and she could return to act on Broadway every year.
She played a newspaperwoman in love with an outlaw (played by Henry Fonda) in the Western "The Return of Frank James". She was then cast in a variety of roles before getting top billing on her own. Her first lead role came in the movie "Heaven can Wait" also starring Don Ameche. She then starred in the Film noir "Laura". This was followed by a second film noir, "Leave her to Heaven". Starring with Tyrone Power, she played the female lead in "The Razor's Edge". Probably her best known film was "The Ghost and Mrs. Muir" with Rex Harrison. When it was released in 1947 it did fairly well. But it did not become a classic until later. She went on to star in several films. But she had a number of personal problems later in her career. This included a love affair gone wrong. As her second husband, she married W. Howard Lee, a rich Houston oilman. She remained happily married to him for 20 years until his death in 1981.
After her marriage to Howard she did only two more films before retiring. Tierney's autobiography was published in 1979. As an actor she had been a heavy smoker, probably to lower her voice. On 6 November 1991 Tierney died of emphysema in Houston, Texas. She is buried in Glenwood Cemetery in Houston, next to her husband, W. Howard Lee.
Thalamus
The thalamus is a symmetrical structure in the brains of vertebrates. It is between the cerebral cortex and midbrain.
It relays sensory and motor signals to the cerebral cortex, and regulates consciousness, sleep, and alertness.
The thalamus sits above the hypothalamus, and below the cerebral cortex. It is a collection of nuclei with various functions. It acts as a relay station, gathering sense information of all kinds (except olfactory) and passes it on to the cerebral cortex.
There are action systems for several types of behaviour, including eating, drinking, defecation, and copulation. These behaviours satisfy short-term needs, and are called 'consummatory' behaviours.
The thalamus has many functions. First of all, it acts as a relay station, or hub. It relays information between subcortical areas and the cerebral cortex. In particular, every sensory system except smelling) has a thalamic nucleus that receives sensory signals and sends them to the related areas in the cortex. For sight, for example, inputs from the retina are sent to the thalamus, which in turn sends them to the visual cortex in the occipital lobe.
The thalamus is believed to process sensory information as well as relay it—each of the primary sensory relay areas gets strong feedback from the cerebral cortex.
The thalamus also plays an important role in regulating states of sleep and wakefulness. Thalamic nuclei have strong connections with the cerebral cortex. These circuits are believed to be involved with consciousness. The thalamus plays a major role in regulating arousal, the level of awareness, and activity. Damage to the thalamus can lead to permanent coma.
The thalamus has a role in the basal ganglia system but this is poorly understood. The thalamus has been thought of as a "relay" that just forwards signals to the cerebral cortex. But research suggests that thalamus is more selective. Many different functions are linked to regions of the thalamus. This is the case for most sensory systems (except the olfactory system), such as the auditory, somatic sensory system, visceral, eating and visual systems. There specific lesions cause specific sensory deficits. A big role of the thalamus is to support the motor and language systems. Much of the circuitry for these systems is shared with the thalamus. The thalamus is "functionally connected" to the hippocampus. This is part of the hippocampal system which is crucial for human episodic event memory.
The information for motor control is a network involving the thalamus as a subcortical motor center. In the brains of primates, the thalamus provides the specific channels from the basal ganglia and cerebellum to the cortical motor areas. In an investigation of the eye movement motor response in three monkeys, the thalamic regions were found to cause antisaccade eye-movement. That is the ability to inhibit the reflexive jerking movement of the eyes in the direction of a presented stimulus. They still look in the direction of the stimulus, but do so in a more controlled manner.
Recent research suggests that the mediodorsal (MD) thalamus may "amplify the connectivity (signaling strength) of just the circuits in the cortex needed for the current context. This helps the flexibility (of the mammalian brain) to make complex decisions by wiring the many associations on which decisions depend into weakly connected cortical circuits". Researchers founds that "enhancing MD activity magnified the ability of mice to "think". This lowered by more than 25 percent their error rate in deciding which conflicting sensory stimuli to follow to find the reward".
In short, the thalamus helps to make mammals more effective at making decisions and living in their natural environment.
The thalamus is a key areas which is involved in what is known as the "half-second delay". This is a perceptual illusion which has only recently been discovered. The discovery is as follows: we perceive events in the world as instantaneous. They happen when we see (hear, sense) them happening. But the processing of visual signals at least is what the thalamus does. Experientially, we see events happening (so we think) without any delay. But in reality "it takes half a second for the brain to organise the data" which comes in from, let us say, vision. But we do not sense that half-second delay at all. Our perception of events is that we see them as they happen.