clock


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clock

(klok) a device for measuring time.
biological clock  the physiologic mechanism which governs the rhythmic occurrence of certain biochemical, physiologic, and behavioral phenomena in living organisms.

clock

(klŏk)
n.
1. An instrument other than a watch for measuring or indicating time, especially a mechanical or electronic device having a numbered dial and moving hands or a digital display.
2. A biological clock.
v. clocked, clocking, clocks
v.tr.
To register or record with a mechanical device: clocked the winds at 60 miles per hour.

clock′er n.

CLOCK

A gene on chromosome 4q12 that encodes a ubiquitously expressed human homolog of the mouse clock gene, which forms a heterodimer with ARNTL and activates E-box element transcription of several circadian clock proteins (e.g., PER1 and PER2). CLOCK is highly expressed in the suprachiasmatic nucleus.

Molecular pathology
CLOCK-ARNTL double mutations in the PAS domains result in syngernistic desensitisation to high levels of CRY on repression of CLOCK-ARNTL transcriptional activity of PER1, disrupting circadian rhythmicity.

clock

(klok)
A device for measuring time.

biological clock

1. An internal system in organisms that influences behavior in a rhythmic manner. Functions such as growth, feeding, secretion of hormones, the rate of drug action, the wake-sleep cycle, the menstrual cycle, and reproduction coincide with certain external events such as day and night, the tides, and the seasons. Biological clocks appear to be set by environmental conditions in some animals, but if these animals are isolated from their environment they continue to function according to the usual rhythm. A gradual change in environment does produce a gradual change in the timing of the biological clock. See: circadian; maladaptation to night work; zeitgeber
2. A colloquial term for the decrease in fertility that accompanies aging, particularly as women approach the age of 35.

Patient discussion about clock

Q. How do you wake up in the morning if your narcolepsy is so severe you can't hear the alarm clock, phone ring? biggest problem is sleep paralysis, can't wake up. Late for work, everything, life is suffering because of severity. Have tried ritalin, natural supplements, hypnosis therapy, Provigal, antidepressants, nothing seems to work. Employer thinks it's an excuse, friends are irritated, I'm at my wits end. Life is spent sleeping more than awake.

A. Narcolepsy cannot yet be cured. But EDS and cataplexy, the most disabling symptoms of the disorder, can be controlled in most patients with drug treatment. Often the treatment regimen is modified as symptoms change. For decades, doctors have used central nervous system stimulants-amphetamines such as methylphenidate, dextroamphetamine, methamphetamine, and pemoline-to alleviate EDS and reduce the incidence of sleep attacks. For most patients these medications are generally quite effective at reducing daytime drowsiness and improving levels of alertness. However, they are associated with a wide array of undesirable side effects so their use must be carefully monitored. Common side effects include irritability and nervousness, shakiness, disturbances in heart rhythm, stomach upset, nighttime sleep disruption, and anorexia. For full article: http://www.ninds.nih.gov/disorders/narcolepsy/detail_narcolepsy.htm#120393201 Hope this helps.

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References in periodicals archive ?
Its movement spins gears that rotate the display-altering wheels of the clock face.
Sobel's tale concerns John Harrison, an obscure English watchmaker from a merchant-class background who believed clocks held the answer.
Durst said he hopes that when people see the lighting fast progression of the digital figures on the debt clock, they will better understand the overwhelming burden of the national debt, and that they will act to stop its growth and begin to repay it -- sooner rather than later -- while they still can.
Clock Hours in Behavioural Science Subjects by Instruction Type
With further improvements since they submitted their new report, the NIST researchers have made a clock that's about 10 times as precise as the world's cesium standard, Bergquist says.
By 2010, all new time clocks installed in California will be required to have self-programming and water-saving features.
a La Crosse Technology Atomic clock, Big Ben and Seiko.
We have about 100 clocks we keep ticking and we will be turning back many of those over the weekend, " said Maz.
Comment: Poor clock management created the hesitation and the loss.
This function is significantly more complicated than a repeater since the recovered data must be stored in an add/drop FIFO synchronously to the recovered clock and pulled out of the FIFO timed to the local reference clock.
Jitter noise has become one of the key design challenges at 90nm and below processes, and our customers are looking for solutions that can accurately determine the impact of jitter on their clock tree," said Dian Yang, General Manager and Vice President of Product Management at Apache.