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. Wrichik Basu

    Engineering Issue with shift registers — PIPO, PISO, SIPO and SISO

    We are currently constructing shift registers in our practicals, and I am facing an issue with the circuits. Posting this in the homework section because it arose out of college (thus, coursework). We have to construct four types of (4-bit) shift registers — SISO, SIPO, PISO and PIPO. I feel...
  2. R

    B Does DCQE show a shift between the two "which path" results?

    The Delayed Choice Quantum Eraser (DCQE) experiment attempts to show that which-path information can be "erased," and interference recovered. I'll refrain from explaining the experiment, and assume you are familiar with the setup. I refer to the Wikipedia page about it, and the original Kim...
  3. Jessie24789

    I Doppler Shift & Christoffel Symbols Issues

    About a month or two ago I started doing simulations of light physics around black holes and yesterday I got a fast Christoffel symbols function for the Schwarzschild metric in cartesian coordinates, but now the photon ring appears flipped. I feel as though it is wrong. But as I am still pretty...
  4. Alia_3

    A Understanding 3D Doppler Shift with Satellites

    I am trying to understand a case of doppler shift if I have two satellite circling the earth with different velocities but the same direction and with different altitudes as well. How I will be able to figure out the doppler shift in three dimension between the two satellite if one of the...
  5. B

    Why does an electron have minimum kinetic energy when its momentum is 2h/λ?

    Solution given: The minimum kinetic energy electrons will arise from a change in photon energy on scattering that is a minimum and this will arise from the smallest wavelength change of the photon. The Compton scattering formula is ∆λ = (h/mc)(1 − cos φ) which is minimised when 1 = cos φ. This...
  6. A

    B Time Shift Reference Point: Earth or Other?

    I have been thinking about the classic example of two twins traveling at different speeds and the effect of time passage. One twin that goes off to travel near the speed of light while the other twin is left on earth. We theorize that the traveling twin will pass through less time and be...
  7. E

    I How does diffusion of high energy electrons shift band structure?

    When an n-type material comes in contact with a p-type material to form pn-junction, electrons with the highest energy in the conduction band will diffuse to the p-side to reach equilibrium so the entire band structure on n-side will shift down relative to p-side as described in the following...
  8. B

    A AC Stark shift in diatomic molecules

    Hello! I am analyzing data from a diatomic molecules with a rotational constant around ##0.2## cm##^{-1}##, for transitions between rotational levels between the ground ##^2\Sigma_{1/2}## and excited ##^2{\Pi}_{1/2}## electronic state. I was wondering if there is a way to approximate the shift...
  9. patric44

    Calculate the isotopic shift of the analogue states for Cr and Mn

    hi guys my nuclear physics professor gave us a hand written notes about a the isospin multiplets of elements, the notes provides a brief not clear introduction to the topic with some formulas for calculations, as following $$ E_{xe} = \Delta\;E_{B}+\Delta\;E_{c} $$ $$ \Delta\;E_{B}=...
  10. M

    A How to simulate an isotope shift measurement

    Hello! My questions are based on this paper talking about King plot non-linearities. Assuming I have 3 isotopes and 2 transitions, I would like to know how well I should measure the transitions (i.e. what uncertainty on the transition value) in order to reach a given sensitivity for the new...
  11. B

    A Power induced shift in rotational transitions for a diatomic molecule

    Hello! I am analyzing some data from some rotational transitions between 2 electronic energy levels in a diatomic molecule. I noticed that for different runs that covered the same regions, the peaks we observe are shifted with respect to each other when the power of the laser driving the...
  12. T

    MTW Ex 21.15 - Curvature independent of Lapse and Shift functions

    Can anyone out there give me a hint as to where to start with this problem? I've been looking at it for a while and can't see a way forward. What exactly is "the curvature itself" here?BTW I think the dynamic initial value equations 21.116 and 21.117 are incorrect. MTW should have inserted to...
  13. A

    I Ship Braking: Blue or Red Doppler Shift?

    Let's imagine we have a ship heading towards our planet. It fires forward thrusters to brake. The ship is long way away. Because the ship decelerates, (slows down towards us) would we see particles from its exhaust doppler shifted blue or red? On the one hand the gas is flying towards Earth, so...
  14. S

    Shift in position of plank when a man moves on it (Centre of mass)

    Lets take the original position of the man to be our origin The plank is uniform so we can assume its mass to be concentrated at its center i.e. 4m from the origin Xcom= m1x1+m2x2/m1+m2 =50(0) +150(4) /50+150 =3m There is no external force on the system so the centre of mass does not move...
  15. Einstein44

    Finding the horizontal shift of a function

    I've never actually done this, so I was wondering if someone could show me how this is done. One way I tried was by simply using ##cos^{-1}## in order to cancel the cosine, but that gave me a different value, so I assume this is not how you are supposed to do this. --> I know I am supposed to...
  16. Y

    Does wire length difference create phase shift?

    When wiring a 240 volt AC circuit, I've always assumed that it's important for L1 and L2 wires to be the exact same length, in order to avoid introducing a phase shift that would reduce peak voltage. Length differences can accumulate when the wires enter a panel and need to go slightly...
  17. rinalai

    [Optics] Questions on the Stokes shift

    Here is my answer to this question: Stokes shift is the difference in wavelength between positions of the band maxima of the excitation and emission spectra of the same electronic transition. When Stokes shift is large, it means there is more energy loss, which is not favorable regarding...
  18. R

    I What is the connection between the Lamb Shift and the g factor?

    German Wikipedia mentions that the g factor is one of the causes of the Lamb Shift. It does not say why and I am trying to find a connection between these two things. Any ideas?
  19. U

    I Phase Speed of Wave in non-relativistic Doppler Shift Derivation

    Consider the situation where an observer at rest on the ground measures the frequency of a siren which is moving away from the observer at speed ##v_{Ex}##. Let ##v_w## be the speed of the sound wave. Let ##\lambda_0##, ##f_0##, ##\lambda_D##, and ##f_D## be the wavelengths and frequencies...
  20. C

    Purely passive RC Phase Shift Oscillator?

    It is possible to build a purely passive RC phase shift oscillator with 2 separate (in the future) RC stages like this? Where there would be 2 RC networks that each provide 180 degrees of phase shift. Of course, there would be a buffer in between the 2 RC networks so that they behave as 2...
  21. nicolewreyford

    Doppler shift between a moving ship on the ocean and a satellite in LEO

    Summary:: I would like to calculate the Doppler shift for a signal sent by a moving ship to a moving satellite. I want to calculate the frequency observed by an LEO satellite when a signal is transmitted from a moving ship. The LEO satellite has a velocity of 7120m/s and orbits at a height of...
  22. J O Linton

    B Doppler Shift of Neutron: Energy & Momentum

    When a photon emitted by a distant galaxy travels across space and is detected at a later time when the universe has expanded by a factor of 2, its wavelength, frequency, energy and momentum are all changed by a factor of 2. If a neutron is emitted with energy E and momentum p and is also...
  23. A

    I Index and bound shift in converting a sum into integral

    Considering the below equality (or equivalency), could someone please explain how the bounds and indices are shifted? $$\sum_{i=2}^{k}(h_i/f_{i-1})=\int_{1}^{k}(h(i)/f(i))di$$
  24. S

    I How Do You Calculate Day-Specific Phase Shifts in Excel for Sine Waves?

    Hi, I have created a sine wave with the following options: 1.) - changing the period/length in days of the sine wave (Cycle Length in Days) 2.) - calculating the start value of the "dummy" so that the sine wave always starts with -1 (Dummy Start at Cycle Trough) when the phase shift is set...
  25. C

    RC Phase Shift Oscillator not Oscillating

    Hello everyone. I am having some trouble with an RC phase shift oscillator that I built as a hobby project. I am completely stuck on this and I just cannot figure it out. My oscillator is not oscillating. Here is the circuit that I am trying to get to work. Taken from...
  26. J O Linton

    B Cosmological Red Shift in a Perfectly Reflecting Box

    When a photon travels from a distant galaxy to us it undergoes an increase in wavelength due to the expansion of the universe during the time of flight. On the other hand, physical objects such as atoms and galaxies do not undergo a similar expansion because they are bound together by...
  27. tworitdash

    MATLAB Creating and recovering a frequency shift in time domain in MATLAB

    I am trying to simulate and process the Doppler signals. My main problem is a little more complex so I am only posting a simple version of it. Task1: I have a time-domain signal with the velocity of the target as mu. I need to change the velocity to mu cos(theta) where theta is a vector from 0...
  28. R

    180 degree phase shift of reflected light

    When light originating from a medium of lower refractive index reflects off a surface of higher refractive index, why does the phase shift by 180 degrees? Stokes relations show that reflection coefficients at the surface are equal but of opposite signs depending on direction of light (i.e...
  29. dvscrobe

    Aliasing Phase Shift: Determining Phase Shift

    How do you determine the phase shift of an aliased signal?
  30. K

    I Spin-Orbit Coupling & Isotope Shift

    Hello! The isotope shift for an atomic transition is usually parameterized as: $$\delta\nu = K\frac{m_1m_2}{m_1-m_2}+F\delta<r^2>$$ where ##m_{1,2}## are the masses of the 2 isotopes, ##\delta<r^2>## is the change in the mean square charge radius between the 2 isotopes and K and F are some...
  31. K

    I Nuclear size effect on isotope shift

    Hello! The transition wavelength between 2 energy levels for an atom depends on the nuclear isotope through the mass of the isotope and the size of the nucleus. My question is only about the nuclear size effect. It can be shown that this effect can be written as (this is basically a taylor...
  32. M

    Minimum Tone Spacing: Coherent Frequency Shift Keying

    Hi, I was reading through some online notes and was wondering: when dealing with coherent FSK, what is the minimum tone spacing and why? I know that for non-coherent FSK, we can show that the minimum is: ## f_1 - f_0 = \frac{1}{T} ## where ## T ## is the symbol period. However, if we are now...
  33. I

    Phase shift between voltage and current

    Hello ,so am trying to find a phase shift between voltage and current ,I've done what do i do after that ?and is this right ? Q A 100Ω load is connected to a power supply of 100V at 50Hz. At time, = 0, the instantaneous value for voltage across the load was zero and the current through the load...
  34. C

    B Conflict Between Time Dilation and Red/Blue Shift?

    Experiment 1: Astronaut travels away from Earth at near the speed of light, then travels toward the Earth at near the speed of light. Einstein tells us she barely aged, but red shift/blue shift don't seem to agree with that. While traveling away, both Earth and astronaut observe each other...
  35. H

    B Explaining Perihelion Shift of Mercury in GR Theory

    Recently, when reading an entry about Mercury's perihelion shift, someone mentioned a "hand-wavy" explanation as to why GR predicts the orbit so precisely. I was wondering if there was some elementary way to expound on what he was saying. Fundamentally, the comment said something to the effect...
  36. P

    Looking for simple mechanisim to shift wing camber

    I am not very good at visualizing mechanisms and how they work. I just looked at all the mechanisms at http://507movements.com/. This is a fun little website and some of the mechanisms have been animated so you can better see how they function. I am trying to build a sailboat wing with...
  37. M

    I Explaining the Bloch-Siegert Shift - A Beginner's Guide

    Hello! Can someone explain to me or point me towards a basic explanation of the Bloch-Siegert shift (even the Wikipedia explanation is not clear to me)? Thank you!
  38. K

    I Understanding the AC Stark Shift Effect in Laser-Atom Interactions

    Hello! I think I am a bit confused about the AC Stark shift effect. Assuming we have a 2 level system with energy difference ##\omega_0## and we apply a laser of frequency ##\omega## and Rabi frequency ##\Omega##. If we look at the problem in a frame rotating at the laser frequency, before we...
  39. Francis

    A Conditional phase shift for Grover's algorithm

    I am trying to understand the following deduction: "The conditional phase shift can be represented by the unitary operator 2|0> <0| - I:" for eq. 4a) I was expecting to be: [2 |0><0| - I] |0> = 2 |0> <0|0> - I|0> = 2|0> - |0> = |0> as for eq. 4b I can't understand it at all. Why does the...
  40. J

    I What is the four-momentum of a photon?

    I'm trying to understand the Energy-Momentum relativistic relationships for a light particles. It is commonly said that the Energy of a photon depends on the observer by the relationship ## E = - \mathbf{p} \cdot \mathbf{u}## where p is the 4-momentum of the source emitting light particles and u...
  41. P

    Why does roofing occur despite the difference in chemical shift?

    J is 7.2 and 7.1 for the triplets (7.2 for the pentet, 7.1 for the sextet), chemical shift 0.93 and 2.62Also is it a AMSX or AMX spinsystem?
  42. M

    Frequency Shift Key Modulation: how are the carrier frequencies chosen

    Question: For frequency shift key modulation in the binary case, how are the two carrier frequencies chosen? From online reading, I have seen that the carriers are chosen to be different but also with the goal of minimising bandwidth and without any overlaps of the spectra, etc. However, I...
  43. D.S.Beyer

    I Red shift / Blue Shift - Gravity Well Roundtrip

    If I shine a white light out into space from Earth, and it bends around a black hole and comes straight back to me so I can see it in my telescope, is the light red or blue shifted, or neither? For sake of the thought experiment, let’s leave out cosmic expansion that would stretch it on it’s...
  44. A

    I Does Acceleration Affect Event Horizon Location?

    Normal acceleration is equivalent to a uniform gravitational field throughout all of space. Thus, if I am normally accelerating, I should observe an event horizon shifted as compared to a non-accelerating observer. Is this correct?
  45. M

    How to 'shift' Fourier series to match the initial condition of this PDE?

    Hi, Question: If we have an initial condition, valid for -L \leq x \leq L : f(x) = \frac{40x}{L} how can I utilise a know Fourier series to get to the solution without doing the integration (I know the integral isn't tricky, but still this method might help out in other situations)? We are...
  46. sekushi0range

    Reason for Ferroin's color shift

    Ferroin is a redox indicator. It is the complexation of phenanthroline and iron. In its reduced state the Fe (II) - phenanthroline complex is red and in its oxidized state the Fe(III)- phenanthroline complex is blue. I am trying to understand in the context of d-d orbital transitions why this is...
  47. P

    Hubble's Law and Doppler Shift

    (a) How far would a galaxy be whose speed with respect to the Earth is ##c##? Would it be observable from the Earth? r=rα=1.5⋅1026 m =1.6⋅1010 lightyears<4.65⋅1010 lightyearsr=rα=1.5⋅1026 m =1.6⋅1010 lightyears<4.65⋅1010 lightyearsr=rα=1.5⋅1026 m =1.6⋅1010 lightyears<4.65⋅1010 lightyears...
  48. Tymofei

    Influence of initial shift on undamped frictionless forced oscillations

    I have general equation for undamped forced oscillations (no friction) which is: I just wonder about,what type of motion should occur when initial conditions are both 0 (i.e v0=0 and x0=0). My intuitive expectation is that as there is no 'natural' oscillations at beginning,vibration has to be...