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(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.


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
To register or record with a mechanical device: clocked the winds at 60 miles per hour.

clock′er n.


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.


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: Hope this helps.

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References in periodicals archive ?
Each byte would require six CPU clock cycles to determine whether or not the FIFO registers do or do not contain valid data (assuming two clock cycles to read the empty/full status bit, two clock cycles to test the empty/full status bit and two clock cycles to read the data byte).
SPYRUS plans to migrate its security solution to Infineon's new 66PE family of secure microcontroller ICs to take advantage of enhanced features including more efficient EEPROM programming, 33MHz CPU clock, and smaller die size.
SPYRUS plans to migrate its security solution to Infineon's new PE family of secure microcontroller ICs to take advantage of enhanced features including more efficient EEPROM programming, 33MHz CPU clock, and smaller die size.
The new controllers feature SDRAM memory that can lock memory access to the CPU clock, resulting in faster data transfer.
The family also features a vector floating-point coprocessor for full support of single-precision and double-precision calculations at CPU clock speeds, which is important for signal processing applications such as motor control.
The clock generator IC offers non-linear spread-spectrum modulation for reduced system electromagnetic interference, and delivers low cycle-to-cycle CPU clock jitter (under 150ps p-p) for improved timing margins.
Xolo's upcoming super smartphone is expected to pack a powerful Intel's 'Clover Trail+' chipset with CPU clock speed.
Burst mode A high-speed data transmission mode in which data read/write is synchronized to an external CPU clock.
For example, the 16-bit asynchronous event counter (AEC) can be used to count input pulse even when the CPU clocks are turned off.
As successor of the well-known V850ES/Fx3 MCUs, the V850E2/Fx4 MCUs incorporate CPU clocks ranging from 48 MHz up to 160 MHz, and flash memory from 256 KB up to 4 MB assembled in packages with pin counts ranging from 64 to 256.
The CM5470 device provides a single-chip clocking solution to drive all of the components commonly implemented alongside MIPS(R) processors, including CPU clocks, USB, LAN, PCI, and RAM clocks.