What is Clock: Definition and 483 Discussions

CLOCK (Circadian Locomotor Output Cycles Kaput) or Clock is a gene encoding a basic helix-loop-helix-PAS transcription factor that is believed to affect both the persistence and period of circadian rhythms.
Research shows that the CLOCK gene plays a major role as an activator of downstream elements in the pathway critical to the generation of circadian rhythms.

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  1. G

    Pendulum of a Grandfather clock

    How does temperature affect grandfather clocks? A metal rod pendulum is inside of the clock. I have a question regarding this. If an expirement happened where 3 clocks were sent to the same time. ONe was put in a cold room, one in a hot, and one in a room temperature room. What would the...
  2. T

    Vector components on the tip of hand on a clock

    Hiya all, I'm stuck on a physics question set for homework. It asks "draw vector diagrams to scale to show the vertical and horizontal components of the velocity of the tip of the hand at quater-past, twenty past, twenty-five past and half past the hour." The hand is 20cm long so using the...
  3. O

    Kinetics of an iodine clock reaction?

    kinetics of an iodine clock reaction? i am currently writing up my lab report (from a week ago, i know, i should do it straight away...) on the kinetics of an iodine clock reaction and am calculating the order of the reaction and have taken a wrong turn in my calculations. instead of going...
  4. S

    Solve Power Problem of Grandfather Clock

    A grandfather clock is powered by the descent of a 4.00 kg weight. If the weight descends through a distance of 0.750 m in 3.00 days, how much power does it deliver to the clock? I used my equations... P=W/t W=F*d therefore P = (F*d)/t F=m*a m=4.00 kg a=1.116x10^-11 ? therefore...
  5. S

    Designing an Innovative Stop Clock

    friends i am making a stop clock.iwant to add certain extra ordinary and good features in itwhich are technicalyy feasable.if anybody has some noble idea in this regard please answer me.
  6. A

    Einstein's Clock Synchronization Convention

    Just a friendly reminder, the first postulate of the special theory of relativity, namely that the speed of light c is the same in all inertial frames, only holds true in view of Einstein's clock synchronization convention. There is no experimental basis whatsoever for preferring this convention...
  7. wolram

    Kyoto-Clock/"The Kyoto Clock: Counting Down to Global Climate Action

    The kyoto Clock http://www.junkscience.com/
  8. D

    Driving 7-Segment Display from 200Hz Clock Signal

    I have a clock module that divides a 500mhz signal to a 200hz signal, and another module that is suppose to use the 200hz clk signal to drive 4 multiplexed 7segment display. My question is how do I input the clock module signal into the 7segment display module?
  9. D

    Clock Shop 10:10: The Classic Meaning

    Have any of u noticed the classic clock hang in the time shops always pointing to 10:10 ? (note: i mean the classical one, not the digital one). Do you know why?
  10. U

    What is the rotational kinetic energy of a clock's hour and minute hands?

    The hour hand and the minute hand of a clock are 2.7m long and 4.5m long and have masses of 60kg and 100kg respectively. Calculate the total rotational kinetic energy of the two hands about the axis of rotation. w=circumfrence/time=2rpi/t=2(2.7m)pi/86400s w=1.96x10^{-4}rad/s...
  11. P

    Grandfather Clock Pendulum: Length, Weight, and Natural Period Calculations

    A grandfather clock contains a pendulum of lenghth 0.99336 m with a weight of 1.4kg. The driving mechanism comprises anohter mass of 2kg which goes down by 0.8m in 7 days in order to keep the amplitude of oscillation of the pendulum to give theta=0.08(<<1). What is the natural period of the...
  12. B

    How many degrees does an hour hand move in one hour?

    If an hour hand moves 1/60th of a degree each minute how many degerees will it move in one hour?
  13. J

    Clock Synchronization: How to Measure Photon Velocity

    Hi, I have been thinking that in order to actually prove Einstein's second postulate of SR about the speed of light (and SR in general) you need to make a one-way measurement of the velocity of individual photons. To do this the clocks at the two ends of the path have to be synchronized. My...
  14. A

    A photonic clock - absolute time

    Having been reading a little about the concept of absolute time and how Einstiens theories ruled it out but at the same time established light as invariant to all observers as absolute. If we built a clock that ticked at a rate determined by a beam of light would not that tick rate be an...
  15. Loren Booda

    Which is more linear, a frictionless or slightly frictional pendulum clock?

    A pendulum (clock) is moderately nonlinear for small angles of displacement. Is simple harmonic motion better approached by introducing a degree of friction into its works?
  16. S

    How to Calculate Error in a Pendulum Clock at Different Temperatures"

    I am trying to solve this question.. A pendulum clock with a pendulum made of brass is designed to keep accurate time at 23 °C. If the clock operates at 0.0°C, what is the magnitude of its error, in seconds per hour (use a minus sign to indicate slowing down)? The linear expansion coefficient...
  17. J

    Thermal expansion and a pendulum clock

    I need a little help. The problem is as follows: A pendulum clock with a pendulum made of brass is designed to keep accurate time at 18 °C. If the clock operates at 0.0°C, what is the magnitude of its error, in seconds per hour (use a minus sign to indicate slowing down)? The linear...
  18. K

    Definition of a clock in relativity theory

    What is the definition of a clock in relativity theory?
  19. M

    The Human Body's Internal Clock: How Does It Keep Time?

    I was just curious as to what mechanism in our body tells time. How is it that we can count 1,2,3,4,5,6,ect to a moderate accuracy? I would guess it gaugues something harmonic, but what do I know. Any help would be Grrrreat!
  20. A

    Question about the light clock

    Question about the "light clock" I'm trying to make sense of Brian Greene's explanations of SR in The Elegant Universe. For those who don't know it, he gives the example of a "light clock" that bounces a single photon between two mirrors and produces a tick after each round-trip. Another...
  21. marcus

    Pullin: most accurate clock possible

    Pullin et al have an article addressing the question what is theoretically the most accurate clock one can build to measure intervals of time less than a certain \inline T_{max} If the clock must be able to time intervals as long as, for example, \inline T_{max} = 1 billion years then how...
  22. B

    Did the Apollo Missions Use an Atomic Clock for Time Dilation Experiments?

    Did they take an atomic clock on one of the Apollo missions for time dilation experiment if not why not ?
  23. D

    How Long is a Mayan Minute? Exploring the Apocryphal Mayan Clock

    Brain Thumper #3 The apocryphal Mayan clock has two faces. The left face is divided into 13 equal sections partitioned by marks that include one pointing straight down. Each section is labeled with a number 1 to 13, starting with a dot at the very top and proceeding clockwise with three dots, a...
  24. D

    Can a pendulum clock be used in an earth satellite

    can a pendulum clock be used in an Earth satellite
  25. Vadim Matveev

    One way Speed of Light measured by a Single Clock

    Let us imagine that a radar located at the terrestrial equator near Quito sends a narrow signal directed eastwards. We shall also imagine, that on all line of equator the set of reflectors is located and that the reflectors thus deflect the radar signal radiated eastwards in Quito, that it...
  26. Y

    Light Clock Thought Experiment: Parallel Moving Mirrors

    I have raised this issue in a different manner before - but never got a satisfactory analysis. In the traditional parallel moving mirrors (separated by distance d) light clock thought experiment, the photon is considered to travel back and forth over the same path in the moving train (both...
  27. S

    Clock postulate calculations?

    Let me start by saying I most likly have no idea what I am doing. Also, that I realize the factor by which the moveing clock differs from the stationary one will be very very small. Sorry if this belongs in the math fourm, i thought it might require physics knowledge. What I'm having problems...
  28. Saint

    Is This the Coolest Clock You've Ever Seen?

    Click this --- Neat Clock http://www.suite101.com/files/mysites/AskAlice/Clock.htm
  29. Greg Bernhardt

    When is the next time Jack' clock will be exactly on time?

    Jack has an antique cuckoo clock. It's a lovely clock, but it runs too slowly; it loses 9 minutes of time every hour. Sam visits his friend Jack one day, and notices that the cuckoo clock is exactly on time at noon on Tuesday. When is the next time Jack' clock will be exactly on time?
  30. D

    Ultrastable Optical Clock with Neutral Atoms in an Engineered Light Shift Trap

    Does someone can explain that? The transition frequency v of atoms exposed to the lattice electric field of E is described as, hv = hv^(0)-(1/4) alpha(e,w)E^2-(1/64) gama(e,w)E^4 where v^(0) is the transition frequency between the unperturbed atomic states, alpha(e,w) and gama(e,w) are...
  31. K

    Measuring One Second: Official Count & Clock Corrections

    What is the official count of one second? What I mean by this is: how would one go about measuring one second exactly? Basically, at the creation of a second, how was it measured? Also, if a day is 23 hours and 56 minutes, wouldn't our clocks be off 4 minutes after each day? I understand the...
  32. Q

    How Does Infrared Data Transfer Work in Electronic Devices?

    I observed with several electronic devices (primarily romote controls) which use infrared light emitting diodes (IR-LEDs) to send data is that with some, if the LED is viewed closely and carefully enough you can see a red light flash when being used. I know that IR light is invisible, and I'm...
  33. D

    Calculating Light Speed and Time Dilation: A Guide to Relativity

    Hi! 1) A fast spaceship is traveling with a speed of .80c. How fast would light travel from the headlights of the ship relative to a stationary observer? I said the answer was .80c because there is no change, I mean on Earth sure it would be different because of the distance it had to...
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