What is Shift: Definition and 653 Discussions

Shift work is an employment practice designed to make use of, or provide service across, all 24 hours of the clock each day of the week (often abbreviated as 24/7). The practice typically sees the day divided into shifts, set periods of time during which different groups of workers perform their duties. The term "shift work" includes both long-term night shifts and work schedules in which employees change or rotate shifts.In medicine and epidemiology, shift work is considered a risk factor for some health problems in some individuals, as disruption to circadian rhythms may increase the probability of developing cardiovascular disease, cognitive impairment, diabetes, and obesity, among other conditions.

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  1. G

    Why does shifting a function to the right require a smaller input variable?

    Homework Statement Could someone please explain, in very simple words, the horizontal shift of a graph? I've used the search button, textbooks, and google and I'm just not comprehending this. Why does the graph f(x-1) shift f(x) 1 unit to the right and not left? Homework Equations...
  2. B

    Validity of the Doppler shift formula?

    The formula which accounts for the Doppler shift is derived from the invarainace of the phase of a plane wave. [1] The plane wave is a mathematical construction associated with an infinite source os oscillation or with a very high source-receiver distance. The same formula is derived...
  3. D

    Why is the phase shift equal?

    At Estevan, Saskatchewan, the latest sunrise time is at 9:12am on Dec 21. The earliest sunrise time is 3:12pm on June 21. Sunrise times on other dates can be predicted from a sinusoidal equation. There is no daylight saving time in Saskatchewan and the period is 365 days. Convert the time into...
  4. Andre

    Farewell Shift | 7-8 Feb 2009 | European Sky

    That's today for me, guarding a piece of the European sky for the last time, in the night of Sat -> Sun 7-8 Feb 2009 and then retirement. :approve: :rolleyes: :frown:
  5. D

    Horizontal Shift of a function

    I'm currently enrolled in College Algebra, and it is possible that I'm making too much out this; however, this is bugging me a bit and I can't quite get my head around it. I understand how to perform the various shifts and stretches of the graph of a function, but I'm trying to reach a better...
  6. N

    Unilateral Shift Homework: Compute SS*, S*S, S^nS^(*n), S^(*n)S^n

    Homework Statement Let S be the unilateral shift and compute SS^* and S^*S. Also compute S^n S^(*n) and S^(*n)S^n Homework Equations The Attempt at a Solution First what is meant by unilateral shift?
  7. D

    Quantum Well & Barrier w/ Phase Shift

    Homework Statement V(x) = \inf if x \leq 0 = -V if 0 < x < a = 0 if x > a NOTE: E>V Find the wave functions in each region and the stated phase shift. Homework Equations Schrodinger Eq. Instructions note that wave functions are: \Psi_I = A\sin{kx} \Psi_{II} =...
  8. R

    No problem, happy to help! Keep up the good work.

    What is the meaning of phase and phase shift?? and How can I obtain phase shift from the sine curve ?? http://www12.0zz0.com/2009/01/16/17/965512159.jpg Note : I'm a begginer in physics , so please if you can , please explain the concept in details .. Thank you ..
  9. P

    Perturbation theory energy shift for hydrogen atom

    I'm trying to follow some working by lecturer; Treating delK (previously found in first bit of question), show that the energy En of the usual hydrogenic state [nlm> is shifted by some expression given. basically we start with \[ \frac{1}{2m_{0}c^{2}} \left\langle...
  10. Y

    What cause a phase shift between Ex and Ey of a polarized EM wave?

    In EM wave polarization. Where is linear polarization where \gamma =0 or \pi . \gamma = +/- 45 deg and amplitude of Ex and Ey are equal to give circular polization etc. My question is why there are different angle of \gamma on the first place? If you set the reference at x...
  11. C

    Any experimental evidence of Doppler shift in light?

    Were there any experiments that proved doppler shift of light on a fast moving object - that it has higher frequency if the object is moving towards you and lower if the object is moving away?
  12. D

    Phase shift upon external reflection

    Hello, this question might not be particularly clear, but I'd like a quantum mechanical description of the classical idea of external reflection by a medium. Now, the way I see it, a photon (or numerous photons if necessary) approach the boundary of a medium. Classically, the reflected wave has...
  13. V

    Special relativity noob problem 2, Dopler shift.

    Homework Statement By 2025 a spaceship shuttle service operates between the Earth and Mars. Each spaceship is equipped with identical mono chromatic head and tail lights, and their cruising speed v relative to earth, is such that the headlight of a homeward-bound spaceship appears green (...
  14. A

    Doppler Shift and Velocity Relationship

    1. Whenever we talk about a single frequency characterizing an electromagnetic wave, we are tacitly assuming that the source and the detector are stationary relative to one another. However, if the distance between the two is changing in velocity, V, then the frequency of radiation, ν1 emitted...
  15. S

    Frequency shift and relative velocity

    Suppose two observers A and B are moving with regard to each other at relative velocity = v = 0.5c, which they have determined for each other by measuring the time interval that a point of the other frame takes to pass by two points of their own frame, whose clocks are synchronized using the...
  16. A

    How Does Speed Affect Radar Frequency Shift?

    Homework Statement What is the frequency shift of a 72 GHz police radar signal when it reflects off a car moving at 111 km/h? (Radar waves travel at the speed of light = 340 m/s.) -------- f' = f(1 +- u/v) (moving observer, + appr, -receding) f' = f/(1 +- u/v) (moving source, - appr...
  17. R

    Solving the Centre of Mass Shift When Ice Melts

    SOLVED Homework Statement A plate of of Mass m contains an ice cube of mass M and side L. Find the shift in centre of mass when th ice melts. (Gravity absent) The Attempt at a Solution I think that the centre of mass will come down by ML/2(M+m) But my book gives it zero. why? What has gravity...
  18. E

    Shielding Effect and Chemical Shift

    Homework Statement Given a molecule of chloroethene (vinyl chloride) or ClCH=CH2. Rank the hydrogen atoms in the molecule in terms of which will have the greatest chemical shift. Homework Equations None The Attempt at a Solution Since the Cl and the double bond are both...
  19. C

    Questions bout the Chloride Shift in R.B.cell

    Hi, i have a question bout the chloride shift that occurs in the red blood cell. After the carbon dioxide has dissociated into the Red Blood Cell's plasma and became H+ and HCO3- i would like to know why must the HCO3- must go out and combine with the Sodium ions and since the H+ ions have...
  20. S

    Blue Shift objects; is there a list/table?

    I know M31 is on the list and I know there aren't a lot of these objects at any distance. Long ago I subscribed to the thought that EM probably fatigues slowly as it propagates through space or any medium for that matter. :-) I would like to see the actual data we have on blue shifted...
  21. S

    Null Physics: A Paradigm Shift in Modern Science?

    I heard about a book called 'null physics' which is supposedly a paradigm shift in modern physics that unifies many aspects of science. Anybody read this book and can clue me into the main ideas? Thanks for the time...I teach science.
  22. Loren Booda

    Does Hubble's law rely on the Doppler shift?

    If not Doppler, what type of transformation does Hubble's law utilize?
  23. J

    What is the approximate gravitational red shift for light emitted by the sun?

    The book gives the equation: \frac{\Delta\textit{v}}{\textit{v}} = \frac{GM}{c^{2}R} the problem gives me the mass of the sun, it's radius, and the wavelength of light being emitted. So basically I can solve the right side of the equation, but I'm just not sure about how to express the amount...
  24. 4

    Analysing an IS Curve Shift with Fixed Interest Rate

    This is an econ question, i am not sure if i should post it here. Assume that initially the IS curve is given by IS1: Y = 12-1.5T-30i+2G, and that the price level P is 1, and the LM curve is given by LM1: M= Y(1-i). Initially, the home interest rate equals the foreign interest rate of 10%...
  25. F

    Finding shift in centre of gravuty

    Homework Statement Find the minimum lateral shift in position of the centre of gravity of a standing man whose mass is 80 kg, when is carrying a 14 kg pail of water. Assume that he wishes to have an equal load on each foot. How is this shift in his centre of gravity accomplished? Homework...
  26. P

    Would Gravity Waves Show Doppler Shift?

    Random question that I thought of while trying to fall asleep last night. :) We all know that galaxies moving very fast away from us exhibit visual redshift. If gravity waves / gravitons are real, they must then have a frequency of some kind. Does the frequency of a gravity wave affect...
  27. Mentz114

    Frequency shift of light between observers in Schwarzschild space-time

    Considering the simple case of two observers O1 and O2 lying on the same radius at positions r=r1 and r=r2 respectively. Using a result from Stephani(1) I work out that the ratio of frequencies of light sent radially between these observers is given by this ratio, numerator and denominator...
  28. C

    Dopler Shift and Photon Number

    Here's something that I recently thought about: If we assume a Doppler shifted EM wave retains the amplitude of the unshifted wave, then we must be creating/annihilating photons. This seems consistent with the conservation of energy; the removal of several photons removes energy from the...
  29. V

    Why is the Doppler shift expression sometimes reversed?

    Hello, I am well and truly stumped on Doppler shift. The complete expression is f'=f \gamma (1-\beta cos(\theta)) where: \beta=v/c v=source\ velocity \gamma=\frac{1}{\sqrt{1-\beta^{2}}} \theta is the angle between received photons (lab frame) and the direction of motion of...
  30. M

    Bacteria Make Major Evolutionary Shift in the Lab

    Bacteria Make Major Evolutionary Shift in the Lab This is pretty cool.
  31. A

    Why do we have red shift and blue shift, and not only one?

    I hardly understand anything about relativity (as would be evident from my threads and posts), and thus, this dumb question. If there is only length contraction, and not length expansion, why do we have two shifts, namely redshift and blue shift? should not only there be only blue shift due to...
  32. N

    Mathematica Discrete Fourier Transform to find phase shift - Mathematica

    If I use the following code in Mathematica f1[t_] := Cos[w t + d1]; f2[t_] := Cos[w t + d2]; data1 = Table[f1[t], {t,1,10000}]; data2 = Table[f2[t], {t,1,10000}]; ft1 = Fourier[data1]; ft2 = Fourier[data2]; To take the Fourier transform of two data sets, how can I use the resulting data...
  33. T

    Relativistic Doppler Shift and a Star breaking up

    Homework Statement A distant star at rest with respect to an observer on Earth emits light of frequency 6.690 x 10^14 Hz. The star breaks up into two remnants of equal mass, which are observed to emit light of frequency 7.135 x 10^14 Hz and 4.282 x 10^14 Hz Find the velocities of the...
  34. T

    Relativistic Doppler Shift Equation - Derivation

    Homework Statement The full expression for the relativitic Doppler Shift is v' = v \gamma [1- \beta cos \theta] where v' and v are the frequencies of the light source in its own rest frame and and in the laboraty respectivley. \theta is the (laboratory) anglebetween the direction of...
  35. Evo

    Can a supercomputer change the way we view statistics?

    This is a cool little video about statistics. I know some are right, most I haven't bothered to verify yet. Anyone that has any statistics that agree or disagree would be welcomed. Of course the part about the supercomputer's capacity and processing doesn't mean it has the ability to think...
  36. A

    Understanding Field Shift: The Doppler Effect and the Speed of Gravity Explained

    Wiki If speed susceptible to Doppler's effect. Why shouldn't field since we're so determine they have a speed?
  37. K

    How can I determine sound direction using stereo signal phase shift?

    Hello everybody. I'm trying to build a sound direction localising subsystem for a robot. I have two microphones placed a distance apart. I'm not worried about sounds behind or the distance, just the direction. I see two choices. Phase shift detection or a neural sim of interaural time...
  38. Hydr0matic

    Oscillating charge, wave shift

    Consider a charge oscillating along the Y axis. EM waves are emitted around it and hits an observer further down the X axis. The charge then gains speed along the X axis, moving towards the observer. He notes a blueshift in the measured EM wave, ie the Doppler effect. My question is... Will...
  39. K

    The red shift - what does it indicate?

    First of all - please don't give me warnings if I write something that is not correct here. I'm just trying to understand the Big Bang theory, and I have some problems with it. OK, the red shift. What does it indicate? I don't believe it indicates velocity and distance, because there are...
  40. U

    Phase, Phase Difference and Phase Shift

    What's the difference between Phase, Phase Difference and Phase Shift in terms of waves? I've taken a look to Wikipedia and a few other sites already, so please do not forward me to them...
  41. Z

    How Does Doppler Shift Explain the Beats Heard from a Moving Car?

    [SOLVED] Doppler Shift and Beats Homework Statement A car horn sounds a pure tone as the car approaches a wall. A stationary listener behind the car hears an average frequency of 250Hz, which pulsates (beats) at 12 Hz. What is the speed of the car? The speed of sound is assumed to be 331...
  42. J

    Le Chatelier's Principle - What is an equilibrium shift?

    [SOLVED] Le Chatelier's Principle - What is an equilibrium shift? When my chemistry textbook says, "the equilibrium shifts to the right", what does it mean? Is it increasing the rate of the forward reaction to accomplish this? If a shift in equilibrium is not a change in the rate of...
  43. P

    . Radio Spectroscopy -> Finding the doppler shift in a graph

    I've been trying this for 3 hours and I'm getting nowhere. These are the graphs I made for Hydrogen Intensity vs Frequency for a radio telescope that transits the sun and galactic arms of the galaxy. http://img220.imageshack.us/img220/5904/helpgraphia6.jpg...
  44. S

    The Doppler Shift - is this right?

    Homework Statement The Doppler shift was first tested in 1845 by the French scientist B. Ballot. He had a trumpet player sound an A 440 Hz while riding on a flatcar pulled by a locomotive. At the same time, a stationary trumpeter played the same note. Ballot heard 3.0 beats per second. How...
  45. B

    Doppler wavelength shift equation

    Can anyone tell me what the doppler wavelength shift equation is? thanks
  46. E

    Redshift Issues: Understanding the Light-Metric Coupling in Cosmology

    I have some issues with the current understanding of the cosmological red shifts and their interpretation using the spatial variation in the metric with time.To make the argument clear, I'm also posting pictures. The universe is depicted as the surface of a sphere but that doesn't affect the...
  47. S

    MATLAB How Can I Time Shift a Signal in Matlab?

    Hi! How can I time shift (ts) a real signal (N samples, T time period, dt sample rate, Fs sampling frequency) using matlab: Timeshift signal = ifft (fft(signal)*exp(2*i*pi*Fs*ts)) ? I am trying to do it this way and it is not working? For example how would you shift a Cos signal to...
  48. O

    Optimizing Phase Shift for Two Waves with Different Wavelengths

    I am working on the following problem. http://img244.imageshack.us/img244/9777/homeworkun4.jpg The Attempt at a Solution I realize that the relative phase shift between ray 1 and ray 2 will be \frac{4L}{\lambda} Next, I let \frac{4L}{\lambda_a}=1 and \frac{4L}{\lambda_b}=1.5 I did this...
  49. W

    Red Shift = Expanding Universe?

    Has anyone ever considered the possibility that the perceived Doppler effect of light from distant stars/galaxies is not caused by movement of the emitting bodies, but rather a side effect of light traveling extraordinarily long distances under the week gravitational force of the entire...
  50. D

    (optics) phase shift definition

    Folks, I've got a question. Is this definition correct? \delta _i = \frac{2\pi}{\lambda_i} * n_i * \cos \, \theta _i where \delta _i is the optical thickness of medium i \lambda _i is the wavelength in medium i (i.e. not \lambda _0, the vacuum wavelength) n_i is the refractive...
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