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Fictitious force

A fictitious force is a force that appears to act on a mass whose motion is described using a non-inertial frame of reference, such as a linearly accelerating or rotating reference frame. Fictitious forces are invoked to maintain the validity and thus use of Newton's second law of motion, in frames of reference which are not inertial.

Passengers in a vehicle accelerating in the forward direction may perceive they are acted upon by a force moving them into the direction of the backrest of their seats for instance. An example in a rotating reference frame may be the impression that it is a force which seems to move objects outward toward the rim of a centrifuge or carousel.

The fictitious force called a pseudo force might also be referred to as a body force. It is due to an object's inertia when the reference frame does not move inertially any more but begins to accelerate relative to the free object. In terms of the example of the passenger vehicle, a pseudo force seems to be active just before the body touches the backrest of the seat in the car. A person in the car leaning forward first moves a bit backward in relation to the already accelerating car, before touching the backrest. The motion in this short period just seems to be the result of a force on the person; i.e., it is a pseudo force. A pseudo force does not arise from any physical interaction between two objects, such as electromagnetism or contact forces. It is just a consequence of the acceleration a of the physical object the non-inertial reference frame is connected to, i.e. the vehicle in this case. From the viewpoint of the respective accelerating frame, an acceleration of the inert object appears to be present, apparently requiring a "force" for this to have happened.

As stated by Iro: "Such an additional force due to nonuniform relative motion of two reference frames is called a pseudo-force."

The pseudo force on an object arises as an imaginary influence when the frame of reference used to describe the object's motion is accelerating compared to a non-accelerating frame. The pseudo force "explains," using Newton's second law mechanics, why an object does not follow Newton's second law and "floats freely" as if weightless. As a frame may accelerate in any arbitrary way, so may pseudo forces also be as arbitrary (but only in direct response to the acceleration of the frame). An example of a pseudo force as defined by Iro is the Coriolis force, maybe better to be called: the Coriolis effect. The gravitational force would also be a fictitious force (pseudo force) in a field model in which particles distort spacetime due to their mass, such as in the theory of general relativity.

Assuming Newton's second law in the form F = ma, fictitious forces are always proportional to the mass m.

The fictitious force that has been called an  inertial force is also referred to as a d'Alembert force, or sometimes as a pseudo force. D'Alembert's principle is just another way of formulating Newton's second law of motion. It defines an inertial force as the negative of the product of mass times acceleration, just for the sake of easier calculations.

(A d'Alembert force is not to be confused with a contact force arising from the physical interaction between two objects, which is the subject of Newton's third law – 'action is reaction'. In terms of the example of the passenger vehicle above, a contact force emerges when the body of the passenger touches the backrest of the seat in the car. It is present for as long as the car is accelerated.)

Four fictitious forces have been defined for frames accelerated in commonly occurring ways:
 * one caused by any acceleration relative to the origin in a straight line (rectilinear acceleration);
 * two involving rotation: centrifugal force and Coriolis effect
 * and a fourth, called the Euler force, caused by a variable rate of rotation, should that occur.

Background
The role of fictitious forces in Newtonian mechanics is described by Tonnelat: "For Newton, the appearance of acceleration always indicates the existence of absolute motion – absolute motion of matter where real forces are concerned; absolute motion of the reference system, where so-called fictitious forces, such as inertial forces or those of Coriolis, are concerned."

Fictitious forces arise in classical mechanics and special relativity in all non-inertial frames. Inertial frames are privileged over non-inertial frames because they do not have physics whose causes are outside of the system, while non-inertial frames do. Fictitious forces, or physics whose cause is outside of the system, are no longer necessary in general relativity, since these physics are explained with the geodesics of spacetime: "The field of all possible space-time null geodesics or photon paths unifies the absolute local non-rotation standard throughout space-time.".

On Earth
The surface of the Earth is a rotating reference frame. To solve classical mechanics problems exactly in an Earthbound reference frame, three fictitious forces must be introduced: the Coriolis force, the centrifugal force (described below) and the Euler force. The Euler force is typically ignored because the variations in the angular velocity of the rotating surface of the Earth are usually insignificant. Both of the other fictitious forces are weak compared to most typical forces in everyday life, but they can be detected under careful conditions. For example, Léon Foucault used his Foucault pendulum to show that a Coriolis force results from the Earth's rotation. If the Earth were to rotate twenty times faster (making each day only ~72 minutes long), people could easily get the impression that such fictitious forces were pulling on them, as on a spinning carousel; people in temperate and tropical latitudes would, in fact, need to hold on in order to avoid being launched into orbit by the centrifugal force.

Detection of non-inertial reference frame
Observers inside a closed box that is moving with a constant velocity cannot detect their own motion; however, observers within an accelerating reference frame can detect that they are in a non-inertial reference frame from the fictitious forces that arise. For example, for straight-line acceleration Vladimir Arnold presents the following theorem: "In a coordinate system K which moves by translation relative to an inertial system k, the motion of a mechanical system takes place as if the coordinate system were inertial, but on every point of mass m an additional 'inertial force' acted: F = −ma, where a is the acceleration of the system K." Other accelerations also give rise to fictitious forces, as described mathematically below. The physical explanation of motions in an inertial frame is the simplest possible, requiring no fictitious forces: fictitious forces are zero, providing a means to distinguish inertial frames from others.

An example of the detection of a non-inertial, rotating reference frame is the precession of a Foucault pendulum. In the non-inertial frame of the Earth, the fictitious Coriolis force is necessary to explain observations. In an inertial frame outside the Earth, no such fictitious force is necessary.

<!--* Figure 1 (centre panel). To an observer at rest on an inertial reference frame (like the ground), the car will seem to accelerate. In order for the passenger to stay inside the car, a force must be exerted on the passenger. This force is exerted by the seat, which has started to move forward with the car and is compressed against the passenger until it transmits the full force to keep the passenger moving with the car. Thus, the forces exerted by the seat are unbalanced, so the passenger is accelerating in this frame.
 * Figure 1 (bottom panel). From the point of view of the interior of the car, an accelerating reference frame, there is a fictitious force pushing the passenger backward, with a magnitude equal to the mass of the passenger times the acceleration of the car. This force pushes the passenger back into the seat until the seat compresses and provides an equal and opposite force. Thereafter, the passenger is stationary in this frame, because the fictitious force and the real force of the seat are balanced.

The accelerating frame is discovered to be non-inertial because, in the accelerating frame, everything appears to be subject to zero net force, and nothing moves. Nonetheless, compression of the seat is observed and is explained in the accelerating frame (and in an inertial frame) by the force of acceleration on the seat from the car on one side, and the opposing force of reaction to acceleration by the passenger on the other. Identification of the accelerating frame as non-inertial cannot be based simply on the compression of the seat, which all observers can explain; rather it is based on the simplicity of the physical explanation for this compression.

The explanation of the seat compression in the accelerating frame requires not only the thrust from the axle of the car but additional (fictitious) forces. In an inertial frame, only the thrust from the axle is necessary. Therefore, the inertial frame has a simpler physical explanation (not necessarily a simpler mathematical formulation), indicating the accelerating frame is a non-inertial frame of reference. In other words, in the inertial frame, fictitious forces are zero. See inertial frame.

This example illustrates how fictitious forces arise from switching from an inertial to a non-inertial reference frame. Calculations of physical quantities (compression of the seat, required force from the axle) made in any frame give the same answers, but in some cases, calculations are easier to make in a non-inertial frame. (In this simple example, the calculations are equally complex for the two frames described.)
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!Animation: driving from block to block In this illustration, the car accelerates after a stop sign until midway up the block, at which point the driver is immediately off the accelerator and onto the brake so as to make the next stop. -->
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Example concerning Circular motion
The effect of a fictitious force also occurs when a car takes the bend. Observed from a non-inertial frame of reference attached to the car, the fictitious force called the centrifugal force appears. As the car enters a left turn, a suitcase first on the left rear seat slides to the right rear seat and then continues until it comes into contact with the closed door on the right. This motion marks the phase of the fictitious centrifugal force as it is the inertia of the suitcase which plays a role in this piece of movement. It may seem that there must be a force responsible for this movement, but actually, this movement arises because of the inertia of the suitcase, which is (still) a 'free object' within an already accelerating frame of reference. After the suitcase has come into contact with the closed door of the car, the situation with the emergence of contact forces becomes current. The centripetal force on the car is now also transferred to the suitcase and the situation of Newton's third law comes into play, with the centripetal force as the action part and with the so-called reactive centrifugal force as the reaction part. The reactive centrifugal force is also due to the inertia of the suitcase. Now however the inertia appears in the form of a manifesting resistance to a change in its state of motion.

Suppose a few miles further the car is moving at constant speed travelling a roundabout, again and again, then the occupants will feel as if they are being pushed to the outside of the vehicle by the (reactive) centrifugal force, away from the centre of the turn.

The situation can be viewed from inertial as well as from non-inertial frames.

 * From the viewpoint of an inertial reference frame stationary with respect to the road, the car is accelerating toward the centre of the circle. It is accelerating, because the direction of the velocity is changing, despite the car having constant speed. This inward acceleration is called centripetal acceleration, it requires a centripetal force to maintain the circular motion. This force is exerted by the ground upon the wheels, in this case, from the friction between the wheels and the road. The car is accelerating, due to the unbalanced force, which causes it to move in a circle. (See also banked turn.)
 * From the viewpoint of a rotating frame, moving with the car, a fictitious centrifugal force appears to be present pushing the car toward the outside of the road (and pushing the occupants toward the outside of the car). The centrifugal force balances the friction between wheels and the road, making the car stationary in this non-inertial frame.

A classic example of a fictitious force in circular motion is the experiment of rotating spheres tied by a cord and spinning around their centre of mass. In this case, the identification of a rotating, non-inertial frame of reference can be based upon the vanishing of fictitious forces. In an inertial frame, fictitious forces are not necessary to explain the tension in the string joining the spheres. In a rotating frame, Coriolis and centrifugal forces must be introduced to predict the observed tension.

In the rotating reference frame perceived on the surface of the Earth, a centrifugal force reduces the apparent force of gravity by about one part in a thousand, depending on latitude. This reduction is zero at the poles, maximum at the equator.
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!Animation: object released from a carousel For someone in the map perspective only one force is sufficient to explain the motion: the red arrow: centripetal force. After release, the number of forces is zero. For someone in the spinning frame the object moves in a complicated way that needs a centrifugal force: the blue arrow.Note: With some browsers, hitting [Esc] will freeze the motion for more detailed analysis. However, the page may have to be reloaded to restart.
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 * Spinframe.gif
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The fictitious Coriolis force, which is observed in rotational frames, is ordinarily visible only in very large-scale motion like the projectile motion of long-range guns or the circulation of the Earth's atmosphere (see Rossby number). Neglecting air resistance, an object dropped from a 50-meter-high tower at the equator will fall 7.7 millimetres eastward of the spot below where it is dropped because of the Coriolis force.

Fictitious forces and work
Fictitious forces can be considered to do work, provided that they move an object on a trajectory that changes its energy from potential to kinetic. For example, consider some persons in rotating chairs holding a weight in their outstretched hands. If they pull their hand inward toward their body, from the perspective of the rotating reference frame, they have done work against the centrifugal force. When the weight is let go, it spontaneously flies outward relative to the rotating reference frame, because the centrifugal force does work on the object, converting its potential energy into kinetic. From an inertial viewpoint, of course, the object flies away from them because it is suddenly allowed to move in a straight line. This illustrates that the work done, like the total potential and kinetic energy of an object, can be different in a non-inertial frame than in an inertial one.

Gravity as a fictitious force
The notion of "fictitious force" also arises in Einstein's general theory of relativity. All fictitious forces are proportional to the mass of the object upon which they act, which is also true for gravity. This led Albert Einstein to wonder whether gravity could be modeled as a fictitious force. He noted that a freefalling observer in a closed box would not be able to detect the force of gravity; hence, freefalling reference frames are equivalent to inertial reference frames (the equivalence principle). Developing this insight, Einstein formulated a theory with gravity as a fictitious force, and attributed the apparent acceleration due to gravity to the curvature of spacetime. This idea underlies Einstein's theory of general relativity. See the Eötvös experiment.
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!Animation: ball that rolls off a cliff
 * Shellframe.gif Note: The rain frame perspective here, rather than being that of a raindrop, is more like that of a trampoline jumper whose trajectory tops out just as the ball reaches the edge of the cliff. The shell frame perspective may be familiar to planet dwellers who rely minute by minute on upward physical forces from their environment, to protect them from the geometric acceleration due to curved spacetime.
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General derivation
Many problems require use of noninertial reference frames, for example, those involving satellites and particle accelerators. Figure 2 shows a particle with mass m and position vector xA(t) in a particular inertial frame A. Consider a non-inertial frame B whose origin relative to the inertial one is given by XAB(t). Let the position of the particle in frame B be xB(t). What is the force on the particle as expressed in the coordinate system of frame B?

To answer this question, let the coordinate axis in B be represented by unit vectors uj with j any of { 1, 2, 3 } for the three coordinate axes. Then
 * $$ \mathbf{x}_\mathrm{B} = \sum_{j=1}^3 x_j \mathbf{u}_j \, . $$

The interpretation of this equation is that xB is the vector displacement of the particle as expressed in terms of the coordinates in frame B at the time t. From frame A the particle is located at:
 * $$\mathbf{x}_\mathrm{A} =\mathbf{X}_\mathrm{AB} + \sum_{j=1}^3 x_j \mathbf{u}_j \, . $$

As an aside, the unit vectors { uj } cannot change magnitude, so derivatives of these vectors express only rotation of the coordinate system B. On the other hand, vector XAB simply locates the origin of frame B relative to frame A, and so cannot include rotation of frame B.

Taking a time derivative, the velocity of the particle is:
 * $$ \frac {d \mathbf{x}_\mathrm{A}}{dt} =\frac{d \mathbf{X}_\mathrm{AB}}{dt} + \sum_{j=1}^3 \frac{dx_j}{dt} \mathbf{u}_j + \sum_{j=1}^3 x_j \frac{d \mathbf{u}_j}{dt} \, . $$

The second term summation is the velocity of the particle, say vB as measured in frame B. That is:
 * $$ \frac {d \mathbf{x}_\mathrm{A}}{dt} =\mathbf{v}_\mathrm{AB}+ \mathbf{v}_\mathrm{B} + \sum_{j=1}^3 x_j \frac{d \mathbf{u}_j}{dt}. $$

The interpretation of this equation is that the velocity of the particle seen by observers in frame A consists of what observers in frame B call the velocity, namely vB, plus two extra terms related to the rate of change of the frame-B coordinate axes. One of these is simply the velocity of the moving origin vAB. The other is a contribution to velocity due to the fact that different locations in the non-inertial frame have different apparent velocities due to the rotation of the frame; a point seen from a rotating frame has a rotational component of velocity that is greater the further the point is from the origin.

To find the acceleration, another time differentiation provides:
 * $$ \frac {d^2 \mathbf{x}_\mathrm{A}}{dt^2} = \mathbf{a}_\mathrm{AB}+\frac {d\mathbf{v}_\mathrm{B}}{dt} + \sum_{j=1}^3 \frac {dx_j}{dt} \frac{d \mathbf{u}_j}{dt} + \sum_{j=1}^3 x_j \frac{d^2 \mathbf{u}_j}{dt^2}. $$

Using the same formula already used for the time derivative of xB, the velocity derivative on the right is:
 * $$\frac {d\mathbf{v}_\mathrm{B}}{dt} =\sum_{j=1}^3 \frac{d v_j}{dt} \mathbf{u}_j+ \sum_{j=1}^3 v_j \frac{d \mathbf{u}_j}{dt} =\mathbf{a}_\mathrm{B} + \sum_{j=1}^3 v_j \frac{d \mathbf{u}_j}{dt}. $$

Consequently, $$

The interpretation of this equation is as follows: the acceleration of the particle in frame A consists of what observers in frame B call the particle acceleration aB, but in addition, there are three acceleration terms related to the movement of the frame-B coordinate axes: one term related to the acceleration of the origin of frame B, namely aAB, and two terms related to the rotation of frame B. Consequently, observers in B will see the particle motion as possessing "extra" acceleration, which they will attribute to "forces" acting on the particle, but which observers in A say are "fictitious" forces arising simply because observers in B do not recognize the non-inertial nature of frame B.

The factor of two in the Coriolis force arises from two equal contributions: (i) the apparent change of an inertially constant velocity with time because rotation makes the direction of the velocity seem to change (a dvB/dt term) and (ii) an apparent change in the velocity of an object when its position changes, putting it nearer to or further from the axis of rotation (the change in $\sum x_j\, d\mathbf{u}_j/dt$ due to change in x j ).

To put matters in terms of forces, the accelerations are multiplied by the particle mass:
 * $$\mathbf{F}_\mathrm{A} = \mathbf{F}_\mathrm{B} + m\mathbf{a}_\mathrm{AB}+ 2m \sum_{j=1}^3 v_j \frac{d \mathbf{u}_j}{dt} + m \sum_{j=1}^3 x_j \frac{d^2 \mathbf{u}_j}{dt^2}\ . $$

The force observed in frame B, FB = maB is related to the actual force on the particle, FA, by
 * $$\mathbf{F}_\mathrm{B} = \mathbf{F}_\mathrm{A} + \mathbf{F}_\mathrm{fictitious},$$

where:
 * $$ \mathbf{F}_\mathrm{fictitious} = -m\mathbf{a}_\mathrm{AB} - 2m\sum_{j=1}^3 v_j \frac{d \mathbf{u}_j}{dt} - m \sum_{j=1}^3 x_j \frac{d^2 \mathbf{u}_j}{dt^2}\, . $$

Thus, problems may be solved in frame B by assuming that Newton's second law holds (with respect to quantities in that frame) and treating Ffictitious as an additional force.

Below are a number of examples applying this result for fictitious forces. More examples can be found in the article on centrifugal force.

Rotating coordinate systems
A common situation in which noninertial reference frames are useful is when the reference frame is rotating. Because such rotational motion is non-inertial, due to the acceleration present in any rotational motion, a fictitious force can always be invoked by using a rotational frame of reference. Despite this complication, the use of fictitious forces often simplifies the calculations involved.

To derive expressions for the fictitious forces, derivatives are needed for the apparent time rate of change of vectors that take into account time-variation of the coordinate axes. If the rotation of frame 'B' is represented by a vector Ω pointed along the axis of rotation with the orientation given by the right-hand rule, and with magnitude given by
 * $$ |\boldsymbol{\Omega} | = \frac {d \theta }{dt} = \omega (t), $$

then the time derivative of any of the three unit vectors describing frame B is
 * $$ \frac {d \mathbf{u}_j (t)}{dt} = \boldsymbol{\Omega} \times \mathbf{u}_j (t), $$

and
 * $$\frac {d^2 \mathbf{u}_j (t)}{dt^2}= \frac{d\boldsymbol{\Omega}}{dt} \times \mathbf{u}_j +\boldsymbol{\Omega} \times \frac{d \mathbf{u}_j (t)}{dt} = \frac{d\boldsymbol{\Omega}}{dt} \times \mathbf{u}_j+ \boldsymbol{\Omega} \times \left[ \boldsymbol{\Omega} \times \mathbf{u}_j (t) \right], $$

as is verified using the properties of the vector cross product. These derivative formulas now are applied to the relationship between acceleration in an inertial frame, and that in a coordinate frame rotating with time-varying angular velocity ω(t). From the previous section, where subscript A refers to the inertial frame and B to the rotating frame, setting aAB = 0 to remove any translational acceleration, and focusing on only rotational properties (see Eq. 1):
 * $$ \frac {d^2 \mathbf{x}_\mathrm{A}}{dt^2}=\mathbf{a}_\mathrm{B} + 2\sum_{j=1}^3 v_j \ \frac{d \mathbf{u}_j}{dt} + \sum_{j=1}^3 x_j \frac{d^2 \mathbf{u}_j}{dt^2},$$
 * $$\begin{align}

\mathbf{a}_\mathrm{A} &= \mathbf{a}_\mathrm{B} +\ 2\sum_{j=1}^3 v_j \boldsymbol{\Omega} \times \mathbf{u}_j (t) + \sum_{j=1}^3 x_j \frac{d\boldsymbol{\Omega}}{dt} \times \mathbf{u}_j \ + \sum_{j=1}^3 x_j \boldsymbol{\Omega} \times \left[ \boldsymbol{\Omega} \times \mathbf{u}_j (t) \right] \\ &=\mathbf{a}_\mathrm{B} + 2 \boldsymbol{\Omega} \times\sum_{j=1}^3 v_j \mathbf{u}_j (t) + \frac{d\boldsymbol{\Omega}}{dt} \times \sum_{j=1}^3 x_j \mathbf{u}_j + \boldsymbol{\Omega} \times \left[\boldsymbol{\Omega} \times \sum_{j=1}^3 x_j \mathbf{u}_j (t) \right]. \end{align}$$ Collecting terms, the result is the so-called acceleration transformation formula:
 * $$\mathbf{a}_\mathrm{A}=\mathbf{a}_\mathrm{B} + 2\boldsymbol{\Omega} \times\mathbf{v}_\mathrm{B} + \frac{d\boldsymbol{\Omega}}{dt} \times \mathbf{x}_\mathrm{B} + \boldsymbol{\Omega} \times \left(\boldsymbol{\Omega} \times \mathbf{x}_\mathrm{B} \right)\, .$$

The physical acceleration aA due to what observers in the inertial frame A call real external forces on the object is, therefore, not simply the acceleration aB seen by observers in the rotational frame B, but has several additional geometric acceleration terms associated with the rotation of B. As seen in the rotational frame, the acceleration aB of the particle is given by rearrangement of the above equation as:

\mathbf{a}_\mathrm{B} = \mathbf{a}_\mathrm{A} - 2\boldsymbol{\Omega} \times \mathbf{v}_\mathrm{B} - \boldsymbol{\Omega} \times (\boldsymbol\Omega \times \mathbf{x}_\mathrm{B}) - \frac{d \boldsymbol\Omega}{dt} \times \mathbf{x}_\mathrm{B}. $$

The net force upon the object according to observers in the rotating frame is FB = maB. If their observations are to result in the correct force on the object when using Newton's laws, they must consider that the additional force Ffict is present, so the end result is FB = FA + Ffict. Thus, the fictitious force used by observers in B to get the correct behaviour of the object from Newton's laws equals:

\mathbf{F}_{\mathrm{fict}} = - 2 m \boldsymbol\Omega \times \mathbf{v}_\mathrm{B} - m \boldsymbol\Omega \times (\boldsymbol\Omega \times \mathbf{x}_\mathrm{B}) - m \frac{d \boldsymbol\Omega}{dt} \times \mathbf{x}_\mathrm{B}. $$

Here, the first term is the Coriolis force, the second term is the centrifugal force, and the third term is the Euler force.

Orbiting coordinate systems
As a related example, suppose the moving coordinate system B rotates with a constant angular speed ω in a circle of radius R about the fixed origin of inertial frame A, but maintains its coordinate axes fixed in orientation, as in Figure 3. The acceleration of an observed body is now (see Eq. 1):
 * $$\begin{align}

\frac {d^2 \mathbf{x}_{A}}{dt^2} &= \mathbf{a}_{AB}+\mathbf{a}_{B} + 2\ \sum_{j=1}^3 v_j \ \frac{d \mathbf{u}_j}{dt} + \sum_{j=1}^3 x_j \ \frac{d^2 \mathbf{u}_j}{dt^2} \\ &=\mathbf{a}_{AB}\ +\mathbf{a}_B\ , \end{align}$$ where the summations are zero inasmuch as the unit vectors have no time dependence. The origin of the system B is located according to frame A at:
 * $$\mathbf{X}_{AB} = R \left( \cos ( \omega t), \ \sin (\omega t) \right) \ ,$$

leading to a velocity of the origin of frame B as:
 * $$\mathbf{v}_{AB} = \frac{d}{dt} \mathbf{X}_{AB} = \mathbf{\Omega \times X}_{AB} \, $$

leading to an acceleration of the origin of B given by:
 * $$\mathbf{a}_{AB} = \frac{d^2}{dt^2} \mathbf{X}_{AB} = \mathbf{ \Omega \ \times } \left( \mathbf{ \Omega \times X}_{AB}\right) = - \omega^2 \mathbf{X}_{AB} \, .$$

Because the first term, which is $$\mathbf{ \Omega \ \times } \left( \mathbf{ \Omega \times X}_{AB}\right)\,, $$ is of the same form as the normal centrifugal force expression: $$\boldsymbol{\Omega} \times \left( \boldsymbol{\Omega} \times \mathbf{x}_B \right)\, ,$$ it is a natural extension of standard terminology (although there is no standard terminology for this case) to call this term a "centrifugal force". Whatever terminology is adopted, the observers in frame B must introduce a fictitious force, this time due to the acceleration from the orbital motion of their entire coordinate frame, that is radially outward away from the centre of rotation of the origin of their coordinate system:
 * $$\mathbf{F}_{\mathrm{fict}} = m \omega^2 \mathbf{X}_{AB} \,, $$

and of magnitude:
 * $$|\mathbf{F}_{\mathrm{fict}}| = m \omega^2 R \, . $$

This "centrifugal force" has differences from the case of a rotating frame. In the rotating frame the centrifugal force is related to the distance of the object from the origin of frame B, while in the case of an orbiting frame, the centrifugal force is independent of the distance of the object from the origin of frame B, but instead depends upon the distance of the origin of frame B from its centre of rotation, resulting in the same centrifugal fictitious force for all objects observed in frame B.

Orbiting and rotating
As a combination example, Figure 4 shows a coordinate system B that orbits inertial frame A as in Figure 3, but the coordinate axes in frame B turn so unit vector u1 always points toward the centre of rotation. This example might apply to a test tube in a centrifuge, where vector u1 points along the axis of the tube toward its opening at its top. It also resembles the Earth–Moon system, where the Moon always presents the same face to the Earth. In this example, unit vector u3 retains a fixed orientation, while vectors u1, u2 rotate at the same rate as the origin of coordinates. That is,
 * $$\mathbf{u}_1 = (-\cos \omega t ,\ -\sin \omega t )\ ;\ $$ $$\mathbf{u}_2 = (\sin \omega t ,\ -\cos \omega t ) \, . $$
 * $$\frac{d}{dt}\mathbf{u}_1 = \mathbf{\Omega \times u_1}= \omega\mathbf{u}_2\ ;$$ $$ \ \frac{d}{dt}\mathbf{u}_2 = \mathbf{\Omega \times u_2} = -\omega\mathbf{u}_1\ \ .$$

Hence, the acceleration of a moving object is expressed as (see Eq. 1):
 * $$\begin{align}

\frac {d^2 \mathbf{x}_{A}}{dt^2}&=\mathbf{a}_{AB}+\mathbf{a}_B + 2\ \sum_{j=1}^3 v_j \ \frac{d \mathbf{u}_j}{dt} + \ \sum_{j=1}^3 x_j \ \frac{d^2 \mathbf{u}_j}{dt^2}\\ &=\mathbf{ \Omega \ \times } \left( \mathbf{ \Omega \times X}_{AB}\right) +\mathbf{a}_B + 2\ \sum_{j=1}^3 v_j\ \mathbf{\Omega \times u_j} \ +\ \sum_{j=1}^3 x_j\ \boldsymbol{\Omega} \times \left( \boldsymbol{\Omega} \times \mathbf{u}_j \right)\\ &=\mathbf{ \Omega \ \times } \left( \mathbf{ \Omega \times X}_{AB}\right) + \mathbf{a}_B + 2\ \boldsymbol{\Omega} \times\mathbf{v}_B\ \ +\ \boldsymbol{\Omega} \times \left( \boldsymbol{\Omega} \times \mathbf{x}_B \right)\\ &=\mathbf{ \Omega \ \times } \left( \mathbf{ \Omega \times} (\mathbf{ X}_{AB}+\mathbf{x}_B) \right) + \mathbf{a}_B + 2\ \boldsymbol{\Omega} \times\mathbf{v}_B\ \, , \end{align}$$ where the angular acceleration term is zero for the constant rate of rotation. Because the first term, which is $$\mathbf{ \Omega \ \times } \left( \mathbf{ \Omega \times} (\mathbf{ X}_{AB}+\mathbf{x}_B) \right)\,, $$ is of the same form as the normal centrifugal force expression: $$\boldsymbol{\Omega} \times \left( \boldsymbol{\Omega} \times \mathbf{x}_B \right)\, ,$$ it is a natural extension of standard terminology (although there is no standard terminology for this case) to call this term the "centrifugal force". Applying this terminology to the example of a tube in a centrifuge, if the tube is far enough from the center of rotation, |XAB| = R ≫ |xB|, all the matter in the test tube sees the same acceleration (the same centrifugal force). Thus, in this case, the fictitious force is primarily a uniform centrifugal force along the axis of the tube, away from the centre of rotation, with a value |Ffict| = ω2 R, where R is the distance of the matter in the tube from the centre of the centrifuge. It is the standard specification of a centrifuge to use the "effective" radius of the centrifuge to estimate its ability to provide centrifugal force. Thus, the first estimate of centrifugal force in a centrifuge can be based upon the distance of the tubes from the centre of rotation, and corrections applied if needed.

Also, the test tube confines motion to the direction down the length of the tube, so vB is opposite to u1 and the Coriolis force is opposite to u2, that is, against the wall of the tube. If the tube is spun for a long enough time, the velocity vB drops to zero as the matter comes to an equilibrium distribution. For more details, see the articles on sedimentation and the Lamm equation.

A related problem is that of centrifugal forces for the Earth–Moon–Sun system, where three rotations appear: the daily rotation of the Earth about its axis, the lunar-month rotation of the Earth–Moon system about its centre of mass, and the annual revolution of the Earth–Moon system about the Sun. These three motions influence the tides.

Crossing a carousel
Figure 5 shows another example comparing the observations of an inertial observer with those of an observer on a rotating carousel. The carousel rotates at a constant angular velocity represented by the vector Ω with magnitude ω, pointing upward according to the right-hand rule. A rider on the carousel walks radially across it at a constant speed, in what appears to the walker to be the straight line path inclined at 45° in Figure 5. To the stationary observer, however, the walker travels a spiral path. The points identified on both paths in Figure 5 correspond to the same times spaced at equal time intervals. We ask how two observers, one on the carousel and one in an inertial frame, formulate what they see using Newton's laws.

Inertial observer
The observer at rest describes the path followed by the walker as a spiral. Adopting the coordinate system shown in Figure 5, the trajectory is described by r(t):
 * $$\mathbf{r}(t) =R(t)\mathbf{u}_R = \begin{bmatrix} x(t) \\ y(t) \end{bmatrix} = \begin{bmatrix} R(t)\cos (\omega t + \pi/4) \\ R(t)\sin (\omega t + \pi/4) \end{bmatrix}, $$

where the added π/4 sets the path angle at 45° to start with (just an arbitrary choice of direction), uR is a unit vector in the radial direction pointing from the centre of the carousel to the walker at the time t. The radial distance R(t) increases steadily with time according to:
 * $$R(t) = s t,$$

with s the speed of walking. According to simple kinematics, the velocity is then the first derivative of the trajectory:
 * $$\begin{align}

\mathbf{v}(t) &= \frac{dR}{dt} \begin{bmatrix} \cos (\omega t + \pi/4) \\ \sin (\omega t + \pi/4) \end{bmatrix} + \omega R(t) \begin{bmatrix} -\sin(\omega t + \pi/4) \\ \cos (\omega t + \pi/4) \end{bmatrix} \\ &= \frac{dR}{dt} \mathbf{u}_R + \omega R(t) \mathbf{u}_{\theta}, \end{align}$$ with uθ a unit vector perpendicular to uR at time t (as can be verified by noticing that the vector dot product with the radial vector is zero) and pointing in the direction of travel. The acceleration is the first derivative of the velocity:
 * $$\begin{align}

\mathbf{a}(t) &= \frac{d^2 R}{dt^2} \begin{bmatrix} \cos (\omega t + \pi/4) \\ \sin (\omega t + \pi/4) \end{bmatrix} + 2 \frac {dR}{dt} \omega \begin{bmatrix} -\sin(\omega t + \pi/4) \\ \cos (\omega t + \pi/4) \end{bmatrix} - \omega^2 R(t) \begin{bmatrix} \cos (\omega t + \pi/4) \\ \sin (\omega t + \pi/4) \end{bmatrix} \\ &=2s\omega \begin{bmatrix} -\sin(\omega t + \pi/4) \\ \cos (\omega t + \pi/4) \end{bmatrix} -\omega^2 R(t) \begin{bmatrix} \cos (\omega t + \pi/4) \\ \sin (\omega t + \pi/4) \end{bmatrix} \\ &=2s\ \omega \ \mathbf{u}_{\theta}-\omega^2 R(t)\ \mathbf{u}_R \,. \end{align}$$ The last term in the acceleration is radially inward of magnitude ω2 R, which is therefore the instantaneous centripetal acceleration of circular motion. The first term is perpendicular to the radial direction, and pointing in the direction of travel. Its magnitude is 2sω, and it represents the acceleration of the walker as the edge of the carousel is neared, and the arc of the circle travelled in a fixed time increases, as can be seen by the increased spacing between points for equal time steps on the spiral in Figure 5 as the outer edge of the carousel is approached.

Applying Newton's laws, multiplying the acceleration by the mass of the walker, the inertial observer concludes that the walker is subject to two forces: the inward radially directed centripetal force and another force perpendicular to the radial direction that is proportional to the speed of the walker.

Rotating observer
The rotating observer sees the walker travel a straight line from the centre of the carousel to the periphery, as shown in Figure 5. Moreover, the rotating observer sees that the walker moves at a constant speed in the same direction, so applying Newton's law of inertia, there is zero force upon the walker. These conclusions do not agree with the inertial observer. To obtain agreement, the rotating observer has to introduce fictitious forces that appear to exist in the rotating world, even though there is no apparent reason for them, no apparent gravitational mass, electric charge or what have you, that could account for these fictitious forces.

To agree with the inertial observer, the forces applied to the walker must be exactly those found above. They can be related to the general formulas already derived, namely:

\mathbf{F}_{\mathrm{fict}} = - 2 m \boldsymbol\Omega \times \mathbf{v}_\mathrm{B} - m \boldsymbol\Omega \times (\boldsymbol\Omega \times \mathbf{x}_\mathrm{B} ) - m \frac{d \boldsymbol\Omega}{dt} \times \mathbf{x}_\mathrm{B}. $$ In this example, the velocity seen in the rotating frame is:
 * $$\mathbf{v}_\mathrm{B} = s \mathbf{u}_R, $$

with uR a unit vector in the radial direction. The position of the walker as seen on the carousel is:
 * $$\mathbf{x}_\mathrm{B} = R(t)\mathbf{u}_R, $$

and the time derivative of Ω is zero for uniform angular rotation. Noticing that
 * $$\boldsymbol\Omega \times \mathbf{u}_R =\omega \mathbf{u}_{\theta} $$

and
 * $$\boldsymbol\Omega \times \mathbf{u}_{\theta} =-\omega \mathbf{u}_R \, ,$$

we find:
 * $$\mathbf{F}_{\mathrm{fict}} = - 2 m \omega s \mathbf{u}_{\theta} + m \omega^2 R(t) \mathbf{u}_R.$$

To obtain a straight-line motion in the rotating world, a force exactly opposite in sign to the fictitious force must be applied to reduce the net force on the walker to zero, so Newton's law of inertia will predict a straight line motion, in agreement with what the rotating observer sees. The fictitious forces that must be combated are the Coriolis force (first term) and the centrifugal force (second term). (These terms are approximate. ) By applying forces to counter these two fictitious forces, the rotating observer ends up applying exactly the same forces upon the walker that the inertial observer predicted were needed.

Because they differ only by the constant walking velocity, the walker and the rotational observer see the same accelerations. From the walker's perspective, the fictitious force is experienced as real, and combating this force is necessary to stay on a straight line radial path holding a constant speed. It is like battling a crosswind while being thrown to the edge of the carousel.

Observation
Notice that this kinematical discussion does not delve into the mechanism by which the required forces are generated. That is the subject of kinetics. In the case of the carousel, the kinetic discussion would involve perhaps a study of the walker's shoes and the friction they need to generate against the floor of the carousel, or perhaps the dynamics of skateboarding if the walker switched to travel by skateboard. Whatever the means of travel across the carousel, the forces calculated above must be realized. A very rough analogy is heating your house: you must have a certain temperature to be comfortable, but whether you heat by burning gas or by burning coal is another problem. Kinematics sets the thermostat, kinetics fires the furnace.

title: Fictitious force


text: Category:Lamar County, Texas

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Category:Lamar County, Texas


text:
Talk:Erythropoietin

Recursion
As a class of drug EPO is an Erythropoietin Stimulating Agent (ESA).

Does anybody else see a problem with this statement? lol Leondegrance (talk) 20:48, 11 July 2008 (UTC)

could
could increased haemoglobin (as a result of lung disease i.e increased producfion of 'erythropoietin' by bone marrow, be a cause of high blood pressure?.

No.GiollaUidir 11:23, 23 March 2006 (UTC)

 * Indeed no, but the hematocrit gets higher and hyperviscosity may develop in extreme cases (rare). JFW | T@lk  16:57, 23 March 2006 (UTC)

Article in french newspaper announced that Lance armstrong might have used EPO. Keep an eye on this?

Recent big article is showing that Erythropoietin could have big role in protecting neurons in CNS:

http://www.clinsci.org/cs/103/0275/cs1030275.htm

Note NYT obituary of Dr. Margot Kruskall, who was one of the early researchers of EPO in the 1980s, and helped to develop the blood test for it. Possibly some of this material could be used (but of course not copied) in the article. --Blainster 22:04, 8 September 2005 (UTC)

Name change
Medical books (e.g. Junqueira's Functional Histology) and dictionaries spell it 'poe', not 'poie'. I changed the title to match this spelling. MrTroy 13:02, 12 April 2006 (UTC)

 * No they don't, at least the ones that are correct do not. I have the Merck manual, Pharmacology (by Rang + Dale), Medical Physiology, even two books on immunology (Janeway and Roitt's) here that all say 'poie'. Not to mention an embarassing defeat on googlefight and, if you care to test, pubmed also. I think I'll change it back to erythropoietin. |→ Spaully°τ 15:13, 12 April 2006 (GMT)

 * I agree with Spaully, "poie" seems to be the most commonly used variation.GiollaUidir 15:55, 12 April 2006 (UTC)

 * Well I wouldn't say the books I own are not "correct". I have books by Junqueira, Robbins, Alberts, the official Farmacotherapeutical Manual of 2005, and a Medical Dictionary which all spell 'poe'. Indeed "Medical Physiology" which you mentioned spells it 'poie'. In fact that's the first book I ever read that spells it that way, I was rather surprised reading that variation. I'm even more surprised hearing that you can name more books spelling 'poie'. Google is an awful source for spelling, by the way, it only reflects how the masses spell a word, not what's the correct spelling.
 * @GiollaUidir: the most common used variation deosn't have to be the good one.
 * I'll leave it 'erythropoietin' for now, I'll only change it back to 'poe' if I manage to gather evidence that that is the correct spelling. Please note I'm not trying to force this spelling on you, I'm just trying to get medical terms correctly spelled within Wikipedia. MrTroy 17:40, 12 April 2006 (UTC)

 * The favor of poie over poe is even larger on scholar.google.com, so if it is an error, is is an error more common in the scientific community than among the masses.--Per Abrahamsen 18:01, 12 April 2006 (UTC)

 * At this point, I think you can hardly call one of the two erroneous. They're both used to such an extent that they're both correct. But the question is which originally was the right one. MrTroy 18:03, 12 April 2006 (UTC)

 * 'poie' I believe is the original as suggested by the increased use of this in other words (haematopoietic, thrombopoietin). Also from the greek 'poiesis' meaning 'making', which fits in with the purpose of the hormone.
 * I agree on google, and usually would never bring it up but in this case the difference is very large. Pubmed queries are closer than my previous post might suggest - 'poie' = 18161, 'poe' = 14972; but if you look at the titles of the 'poe' result they either contain 'erythropoietin' or 'epoetin', seemingly a shortening. I am not accusing you of bad faith, if my previous post seemed a little short it was because of all the pages you had changed.
 * I sould also note that the dictionary you link to also has an entry for the 'erythropoietin', where many dictionaries contain no entry for the 'poe' version. At least for now, and the forseeable future, I think we should stick with the 'poie' version, until this version pervades the medical system. |→ Spaully°τ 18:15, 12 April 2006 (GMT)
 * ...or until someone proves that another spelling is 'the correct one'. But I agree on not changing it for the time being. MrTroy 20:14, 12 April 2006 (UTC)
 * I believe the confusion may arise from the fact that erythropoietin is correctly spelt with an i, whereas epoetin is spelt without. But, to settle the dispute, since a few of my textbooks also say erythropoetin, should it be put as an alternative spelling at the top? Yes, it should, I believe. —Preceding unsigned comment added by 77.100.4.112 (talk) 16:48, 3 January 2009 (UTC)
 * Interesting etymology fact: -poietin comes from the greek word poietes which means 'maker' ("erythrocyte maker"). HrEkstedt (talk) 07:19, 9 April 2019 (UTC)

Pronunciation
I'm really not sure about the pronunciation given here - although it may be the US form. I'm adding a British version. Wee Jimmy (talk) 12:15, 26 September 2014 (UTC)

The pronunciation as I added was exactly according to Wikipedia's style guide. The current revision isn't. Your statement that it's "more common IPA representation style" may be correct, but let's follow Wikipedia's style guide, OK? MrTroy 11:28, 15 April 2006 (UTC)

Veterinary use
I'm not Italic textevenItalic text qualified to edit this page, however I think somebody more qualified might want to mention that erythropoietin is also used (semi-experimentally) in domestic animals.

Basesurge 06:09, 23 February 2007 (UTC)

could increased haemoglobin (as a result of lung disease i.e increased production of 'erythropoietin' by bone marrow, be a cause of high blood pressure?.

No.GiollaUidir 11:23, 23 March 2006 (UTC)

 * Indeed no, but the hematocrit gets higher and hyperviscosity may develop in extreme cases (rare). JFW | T@lk  16:57, 23 March 2006 (UTC)

Article in french newspaper announced that Lance Armstrong might have used EPO. Keep an eye on this?

Recent big article is showing that Erythropoietin could have big role in protecting neurons in CNS:

http://www.clinsci.org/cs/103/0275/cs1030275.htm

Note NYT obituary of Dr. Margot Kruskall, who was one of the early researchers of EPO in the 1980s, and helped to develop the blood test for it. Possibly some of this material could be used (but of course not copied) in the article. --Blaster 22:04, 8 September 2005 (UTC)

Name change
Medical books (e.g. Junqueira Functional Histology) and dictionaries spell it 'Poe', not 'poie'. I changed the title to match this spelling. MrTroy 13:02, 12 April 2006 (UTC)

 * No they don't, at least the ones that are correct do not. I have the Merck manual, Pharmacology (by Rang + Dale), Medical Physiology, even two books on immunology (Janeway and Roitt's) here that all say 'poie'. Not to mention an embarrassing defeat on googlefight and, if you care to test, pubmed also. I think I'll change it back to erythropoietin. |→ Pauly°τ 15:13, 12 April 2006 (GMT)

 * I agree with Spaully, "poie" seems to be the most commonly used variation.GiollaUidir 15:55, 12 April 2006 (UTC)

 * Well I wouldn't say the books I own are not "correct". I have books by Junqueira, Robbins, Alberts, the official Pharmacotherapeutical Manual of 2005, and a Medical Dictionary which all spell 'Poe'. Indeed "Medical Physiology" which you mentioned spells it 'poie'. In fact that's the first book I ever read that spells it that way, I was rather surprised reading that variation. I'm even more surprised hearing that you can name more books spelling 'poie'. Google is an awful source for spelling, by the way, it only reflects how the masses spell a word, not what's the correct spelling.
 * @GiollaUidir: the most common used variation doesnt have to be the good one.
 * I'll leave it 'erythropoietin' for now, I'll only change it back to 'Poe' if I manage to gather evidence that that is the correct spelling. Please note I'm not trying to force this spelling on you, I'm just trying to get medical terms correctly spelled within Wikipedia. MrTroy 17:40, 12 April 2006 (UTC)

 * The favor of poie over Poe is even larger on scholar.google.com, so if it is an error, is is an error more common in the scientific community than among the masses.--Per Abrahamsen 18:01, 12 April 2006 (UTC)

 * At this point, I think you can hardly call one of the two erroneous. They're both used to such an extent that they're both correct. But the question is which originally was the right one. MrTroy 18:03, 12 April 2006 (UTC)

 * 'poie' I believe is the original as suggested by the increased use of this in other words (hematopoietic, thrombopoietin). Also from the Greek 'poiesis' meaning 'making', which fits in with the purpose of the hormone.
 * I agree on Google, and usually would never bring it up but in this case the difference is very large. Pubmed queries are closer than my previous post might suggest - 'poie' = 18161, 'Poe' = 14972; but if you look at the titles of the 'Poe' result they either contain 'erythropoietin' or 'epoetin', seemingly a shortening. I am not accusing you of bad faith, if my previous post seemed a little short it was because of all the pages you had changed.
 * I could also note that the dictionary you link to also has an entry for the 'erythropoietin', where many dictionaries contain no entry for the 'Poe' version. At least for now, and the foreseeable future, I think we should stick with the 'poie' version, until this version pervades the medical system. |→ Spaully°τ 18:15, 12 April 2006 (GMT)
 * ...or until someone proves that another spelling is 'the correct one'. But I agree on not changing it for the time being. MrTroy 20:14, 12 April 2006 (UTC)

Pronunciation
The pronunciation as I added was exactly according to Wikipedia style guide. The current revision isn't. Your statement that it's "more common IPA representation style" may be correct, but let's follow Wikipedia style guide, OK? MrTroy 11:28, 15 April 2006 (UTC)

There should also be a pronunciation for people in the United States. I'm a freaking novelist and I can't make heads or tails out of that silly pronunciation method, even after reading the so-called explanation. That "International Phonetic Alphabet" isn't really used or widely known in the United States. Especially since this is the first I've ever seen or heard of it, I'd say there should be another entry for American English speakers. As it stands, I have no clue how to pronounce this word.

--12.201.55.10 (talk) 05:20, 17 December 2007 (UTC)Brandon Harwell

Veterinary Use
I'm not Italic textevenItalic text qualified to edit this page, however I think somebody more qualified might want to mention that erythropoietin is also used (semi-experimentally) in domestic animals.

Basesurge 06:09, 23 February 2007 (UTC)

Adverse Affect
13.0 g/ml seems to low a number here. I don't have full text access to the article, but the abstract would seem to indicate normal is 13.0 - 15.0 g/dl. Anyone care to expand or correct?

Ganesha 04:42, 11 April 2007 (UTC)

 * EPO is a reasonably safe way to increase hgb from "very low" to the bottom end of the normal range. Trying to reach the middle of the normal range is unsafe.  The goal should normally be somewhere between 10 and 12 g/dL.  (Remember that you're just trying to avoid a need for a blood transfusion with this.  It doesn't really "make you feel better" or "give you more energy.")  WhatamIdoing (talk) 01:08, 18 February 2008 (UTC)

time to take effect
How long does a change in altitude take to cause EPO to restore oxygen availability?

 * You may also wish to try Wikipedia's Reference desk for questions such as this.  Best wishes. Marycontrary 13:56, 25 July 2007 (UTC)

Erythropoietin and blood doping
I am not scientifically qualified to make edits on this page, but I am knowledgeable enough to know that EPO and recombinant EPO are not the same. The main EPO page discusses blood doping as if the natural hormone EPO is what's being abused, when in reality, it is the artificial hormone found in drugs such as epogen. I think people use the term "EPO" too generically and confuse naturally occuring EPO with the rEPO drugs which are widely abused by endurance athletes. The page should refer people interested in the topic of blood doping to a page on recombinant EPO.
 * I think the second paragraph of the article identifies the difference and the proper nomenclature: ESA.BillpSea (talk) 21:25, 2 August 2008 (UTC)

 * No, the second paragraph does not make a distinction. It actually encourages the confusion with the following statement: "This substance was finally purified and confirmed as erythropoietin, opening doors to therapeutic uses for Epo in diseases like anemia."  Because it does not discuss the development of recombinant EPO versus naturally occuring EPO.  This shortcoming of the article helps propogate the misconception that "EPO" is a drug.  Recombinant EPO is a drug, but EPO itself is a naturally occuring hormone.

I think the article is very poorly written, and uses nomenclature in a very simplistic way. —Preceding unsigned comment added by 205.241.11.6 (talk) 20:36, 15 August 2008 (UTC)

billiards
An EPO masking agent was detected in a billiards player. The article conveys this fact as if it is popular to use EPO to enhance billiards play.  MM962 (talk) 23:22, 7 March 2009 (UTC)
 * The original link is dead so I would suggest using archive.org. A "jokes and fails" section should be instituted for reporting news like this. I hope they also strictly test chess players. Money wisely spent.
 * http://web.archive.org/web/20080607111344/http://www.iht.com/articles/ap/2008/03/17/sports/EU-SPT-Doping-Billiards.php — Preceding unsigned comment added by Bstard12 (talk • contribs) 08:52, 30 January 2012 (UTC)

Genetic Engineering
The article didn't really go into the process of how EPO is made and used in the lab. I'm trying to find some sites, but nothing seems to be coming up. 99.230.7.159 (talk) 17:58, 2 April 2009 (UTC)

Location of production
First paragraph: "...it is produced by the peritubular capillary endothelial cells in the kidney..." Several USMLE review books that I've seen say this same thing, but it looks like they're actually produced by fibroblasts in the cortical interstitium. See http://www.ncbi.nlm.nih.gov/pubmed/9402140 and http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=18575881 Can anyone find evidence to dispute this? Sirmky (talk) 06:46, 28 September 2009 (UTC)

 * you are correct, I have modified/corrected this. Please see comprehensive clinical nephrology 4th ed, p951. Kitkat21 (talk) 01:57, 4 October 2011 (UTC)

Proposal to move portions of this article to Epoetin alfa
This article currently is very confusing because it mixes information about the endogenously produced erythropoietin hormone and recombinantly manufactured erythropoetin that is administered as a drug. Hence I propose that this article focus on the erythropoietin gene/protein and the drug specific parts be move to Epoetin alfa (analogous to the insulin and insulin therapy articles). Furthermore this article should conform to WP:MCBMOS while the drug specific article should conform to WP:PHARMMOS. Boghog (talk) 05:45, 12 April 2012 (UTC)

 * ✅ Since no one has objected to the above suggestion, I have gone ahead and moved thhe drug specific material from Erythropoietin to Epoetin alfa and reorganized both articles a bit. Boghog (talk) 06:14, 21 July 2012 (UTC)

Armstrong afficiandos creating biased POV
"The report contained affidavits from numerous riders on the team including Frankie Andreu, Tyler Hamilton, George Hincapie, Floyd Landis, Levi Leipheimer, and several others describing wide spread EPO use during the Tour de France and other bicycling races around the turn of the century. They also implicated Lance Armstrong."

USADAs report is not focused on widespread EPO use in the peleton. Its primary focus is this: that Lance Armstrong: (i) cheated, and (ii) the necessary corollary: that Lance Armstrong is a liar. They did not "implicate" Armstrong. USADA and USADAs witnesses, who have testified on pain of perjury state openly and clearly that Armstrong is a drug cheat. No "implication". No innuendo. it's not as if his name was mentioned in passing and he was 'implicated' in the event, but he's clearly innocent. no no no. Given the evidence and Armstrong's lack of testimony, he has effectively entered a guilty plea as far as USADA and the UCI are concerned.

It is patently obvious that Armstrong's PR machine (guys you can't win the editing war - you are paid whereas wiki users are not. we'll be here forever reverting the changes) or the few supporters he has are making these pro-armstrong edits despite the overwhelming evidence to the contrary. nearly the whole US Postal and Discovery channel have admitted to using performance enhancing substances - lance armstrong is the only one, according to his story, who is clean.

guys, USADA is very clear on this point: Armstrong is a cheat. Fact. Period.

Captainandrewwiggins (talk) 22:48, 7 November 2012 (UTC) Captainandrewwiggins (talk) 23:05, 7 November 2012 (UTC)

Recent evidence
...suggests that EPO may not work as a performance-enhancing drug: http://www.eurekalert.org/pub_releases/2012-12/w-edi120412.php

Probably worth mentioning on this page? ed g2s • talk 17:21, 16 January 2013 (UTC)

Seems to me not much doubt that it increases hematocrit, and that is performance enhancing in endurance sports that depend on getting oxygen to muscles. Might be much less useful for other sports. Gah4 (talk) 02:07, 14 April 2014 (UTC)

Structure and Chemistry Lacking
There really needs to be actual chemical structure or name, including the specific amino acid sequence, the genes involved, and the types/locations of glycoslyations (the terms alfa, beta, etc. are virtually meaningless, with no explanations given even on their respective pages). The synthesis and regulation section only talks about regulation, not the actual synthesis or process for different glycosylations. The PDB structure is colorized but does not indicate the various atoms or even which parts are protein and which are glycans. Lakshwadeep (talk) 21:58, 23 April 2013 (UTC)

Dubious
The statement When exogenous EPO is used as a performance-enhancing drug,[dubious – discuss] it is classified as an erythropoiesis-stimulating agent (ESA). needs clarification.

By search, I find that :
 * its referenced here.
 * the statement is a copyvio!

Request some-one who knows more on this issue to:
 * clarify the contaxt.
 * paraprase & remove the copyvio.

may please see!

AshLin (talk) 10:49, 17 June 2014 (UTC)
 * WP:COPYVIO cleaned and several clarification edits made. Thanks for the prod. Regards.
 * FeatherPluma (talk) 23:20, 17 June 2014 (UTC)
 * Thanks, AshLin (talk) 03:22, 18 June 2014 (UTC)
 * Thanks, AshLin (talk) 03:22, 18 June 2014 (UTC)

Merge Dynepo in
There seem to have been no objections to merge a page for an EPO brand (Dynepo) into this generic page since it was proposed in June 2014. It seems like a good idea to me, as there is little specific on that page.Klbrain (talk) 19:27, 31 August 2015 (UTC)

Article merged: See old talk-page here

Beginning of EPO use in cycling
The article currently states

'Synthetic EPO is believed to have come into use in cycling about 1990'

In the book 'Het laatste geel', former professional Mathieu Hermans admits to using EPO during the 1989 Tour de France. He adds that he did nothing illegal, as it was not yet on the banned substances list yet. — Preceding unsigned comment added by 195.22.11.246 (talk) 13:05, 2 October 2015 (UTC)

External links modified
Hello fellow Wikipedians,

I have just added archive links to 1 one external link on Erythropoietin. Please take a moment to review my edit. If necessary, add after the link to keep me from modifying it. Alternatively, you can add to keep me off the page altogether. I made the following changes:
 * Added archive https://web.archive.org/20121016045710/http://www.bbc.co.uk:80/programmes/b01ngqxd to http://www.bbc.co.uk/programmes/b01ngqxd+

When you have finished reviewing my changes, please set the checked parameter below to true to let others know.

Cheers. —cyberbot II  Talk to my owner :Online 09:56, 17 October 2015 (UTC)

This link "Safety Labeling Changes: Epogen/Procrit (epoetin alfa) and Aranesp (darbepoetin alfa)" goes to a 404 now. Juliansteinb (talk) 18:36, 26 April 2019 (UTC)

Stuff moved to Erythropoiesis-stimulating agent
Not everyone is going to like my attempt to detach the physiological role of erythropoietin and its pharmacological use, but I think it is needed. The content about pharmacological use and misuse is now on Erythropoiesis-stimulating agent (taken from ). Happy to be shot down, but I think it is helpful. JFW | T@lk  11:41, 17 February 2016 (UTC)

Sections
User:IiKkEe this article should follow WP:MCBMOS in its structure. Jytdog (talk) 20:37, 8 September 2017 (UTC)
 * (talk) If I have inadvertently done something wrong, please fix it with an edit.     Regards IiKkEe (talk) 20:49, 8 September 2017 (UTC)

 * (talk) I have reviewed my edits: I have not changed the structure of this Article - all my edits were within Sections. I plead "not guilty". Are you seeing something that I am missing? Regards IiKkEe (talk) 23:44, 13 September 2017 (UTC)

LINK to Jehovah's Witness and Blood Transfusions
I fail to see any need for this unrelated LINK to Jehovah's Witness and Blood Transfusions — Preceding unsigned comment added by 137.118.161.59 (talk) 14:33, 20 February 2022 (UTC)

title: Talk:Erythropoietin


text:
Steroid hormone receptor

Steroid hormone receptors are found in the nucleus, cytosol, and also on the plasma membrane of target cells. They are generally intracellular receptors (typically cytoplasmic or nuclear) and initiate signal transduction for steroid hormones which lead to changes in gene expression over a time period of hours to days. The best studied steroid hormone receptors are members of the nuclear receptor subfamily 3 (NR3) that include receptors for estrogen (group NR3A) and 3-ketosteroids (group NR3C). In addition to nuclear receptors, several G protein-coupled receptors and ion channels act as cell surface receptors for certain steroid hormones.

A steroid hormone receptor is a protein molecule located either within the cell cytoplasm or nucleus that specifically binds to steroid hormones, such as estrogen, progesterone, and testosterone, leading to the activation or suppression of gene expression and subsequent cellular responses. This interaction is crucial for mediating the physiological effects of steroid hormones in various tissues and organs of the body.

Types
Steroid hormone receptors can be categorized into several types based on their specific ligands and functions:

1.Estrogen Receptors (ER): There are two subtypes, ERα and ERβ, which bind to the hormone estrogen. They regulate gene expression in response to estrogen, playing essential roles in reproductive tissues, bone metabolism, and cardiovascular health.

2.	Progesterone Receptors (PR): PRs bind to the hormone progesterone and regulate gene expression in response to its signaling. They are critical for various reproductive processes, including menstruation, pregnancy, and mammary gland development.

3.	Androgen Receptors (AR): These receptors bind to androgens such as testosterone and dihydrotestosterone (DHT). They play key roles in the development and function of male reproductive organs, as well as in secondary sexual characteristics and muscle growth.

4.	Glucocorticoid Receptors (GR): GRs bind to glucocorticoids like cortisol and regulate gene expression in response to stress and metabolic signals. They are involved in processes such as immune response, metabolism, and stress adaptation.

5.	Mineralocorticoid Receptors (MR): MRs primarily bind to mineralocorticoids such as aldosterone and regulate electrolyte balance and blood pressure by controlling ion transport in epithelial cells of the kidney and other tissues.

Nuclear receptors
Steroid receptors of the nuclear receptor family are all transcription factors. Depending upon the type of receptor, they are either located in the cytosol and move to the cell nucleus upon activation, or remain in the nucleus waiting for the steroid hormone to enter and activate them. This uptake into the nucleus is facilitated by nuclear localization signal (NLS) found in the hinge region of the receptor. This region of the receptor is covered up by heat shock proteins (HSPs) which bind the receptor until the hormone is present. Upon binding by the hormone the receptor undergoes a conformational change releasing the HSP, and the receptor together with the bound hormone enter the nucleus to act upon transcription.

 * Nuclear receptors
 * Subfamily 3: Estrogen Receptor-like
 * Group A: Estrogen receptor	(Sex hormones: Estrogen)
 * 1: Estrogen receptor-α	(ERα; NR3A1, )
 * 2: Estrogen receptor-β	(ERβ; NR3A2, )
 * Group C: 3-Ketosteroid receptors
 * 1: Glucocorticoid receptor	(GR; )	(Cortisol)
 * 2: Mineralocorticoid receptor	(MR; )	(Aldosterone)
 * 3: Progesterone receptor	(PR; NR3C3, )	(Sex hormones: Progesterone)
 * 4: Androgen receptor	(AR; NR3C4, )	(Sex hormones: Testosterone)

Structure
Intracellular steroid hormone receptors share a common structure of four units that are functionally homologous, so-called "domains":

 * 1) Variable domain: It begins at the N-terminal and is the most variable domain between the different receptors.
 * 2) DNA binding domain: This centrally located highly conserved DNA binding domain (DBD) consists of two non-repetitive globular motifs where zinc is coordinated with four cysteine and no histidine residues. Their secondary and tertiary structure is distinct from that of classic zinc fingers. This region controls which gene will be activated. On DNA it interacts with the hormone response element (HRE).
 * 3) Hinge region: This area controls the movement of the receptor to the nucleus.
 * 4) Hormone binding domain: The moderately conserved ligand-binding domain (LBD) can include a nuclear localization signal, amino-acid sequences capable of binding chaperones and parts of dimerization interfaces. Such receptors are closely related to chaperones (namely heat shock proteins hsp90 and hsp56), which are required to maintain their inactive (but receptive) cytoplasmic conformation. At the end of this domain is the C-terminal. The terminal connects the molecule to its pair in the homodimer or heterodimer. It may affect the magnitude of the response.

Genomic
Depending on their mechanism of action and subcellular distribution, nuclear receptors may be classified into at least two classes. Nuclear receptors that bind steroid hormones are all classified as type I receptors. Only type I receptors have a heat shock protein (HSP) associated with the inactive receptor that will be released when the receptor interacts with the ligand. Type I receptors may be found in homodimer or heterodimer forms. Type II nuclear receptors have no HSP, and in contrast to the classical type I receptor are located in the cell nucleus.

Free (that is, unbound) steroids enter the cell cytoplasm and interact with their receptor. In this process heat shock protein is dissociated, and the activated receptor-ligand complex is translocated into the nucleus. It is also related to EAATs.

After binding to the ligand (steroid hormone), steroid receptors often form dimers. In the nucleus, the complex acts as a transcription factor, augmenting or suppressing transcription particular genes by its action on DNA.

Type II receptors are located in the nucleus. Thus, their ligands pass through the cell membrane and cytoplasm and enter the nucleus where they activate the receptor without release of HSP. The activated receptor interacts with the hormone response element and the transcription process is initiated as with type I receptors.

Non-genomic
The cell membrane aldosterone receptor has shown to increase the activity of the basolateral Na/K ATPase, ENaC sodium channels and ROMK potassium channels of the principal cell in the distal tubule and cortical collecting duct of nephrons (as well as in the large bowel and possibly in sweat glands).

There is some evidence that certain steroid hormone receptors can extend through lipid bilayer membranes at the surface of cells and might be able to interact with hormones that remain outside cells.

Steroid hormone receptors can also function outside the nucleus and couple to cytoplasmic signal transduction proteins such as PI3k and Akt kinase.

Other
Steroid hormone receptors exert their effects through several mechanisms, including:

1.	Gene Regulation: Upon ligand binding, steroid hormone receptors translocate to the nucleus, where they bind to specific DNA sequences called hormone response elements (HREs) within the regulatory regions of target genes. This binding either activates or suppresses gene transcription, leading to changes in mRNA levels and ultimately protein synthesis.

2.	Transcriptional Coactivators and Corepressors: Steroid hormone receptors recruit coactivator or corepressor proteins to the gene promoter regions, which modulate the activity of RNA polymerase and other transcriptional machinery, thereby influencing gene expression.

3.	Chromatin Remodeling: Steroid hormone receptors can also induce changes in chromatin structure through the recruitment of chromatin remodeling complexes. This allows for accessibility of the transcriptional machinery to specific gene regulatory regions, facilitating or inhibiting gene transcription.

4.	Non-Genomic Signaling: In addition to classical genomic actions, steroid hormone receptors can initiate rapid, non-genomic signaling pathways in the cytoplasm or at the cell membrane. These pathways involve activation of various protein kinases and other signaling molecules, leading to rapid cellular responses such as ion fluxes, cytoskeletal rearrangements, and activation of second messenger systems.

5.	Cross-Talk with Other Signaling Pathways: Steroid hormone receptors can also interact with and modulate the activity of other signaling pathways, such as growth factor signaling pathways, thereby integrating hormonal and growth factor signals to regulate cellular processes.

A new class of steroid hormone receptors has recently been elucidated and these new receptors are found on the cell membrane. New studies suggest that along with the well documented intracellular receptors that cell membrane receptors are present for several steroid hormones and that their cellular responses are much quicker than the intracellular receptors.

G protein-coupled receptors
GPCR linked proteins most likely interact with steroid hormones through an amino acid consensus sequence traditionally thought of as a cholesterol recognition and interaction site. About a third of Class A GPCRs contain this sequence. The steroid hormones themselves are different enough from one another that they do not all affect all of the GPCR linked proteins; however, the similarities between the steroid hormones and between the receptors make plausible the argument that each receptor may respond to multiple steroid hormones or that each hormone could affect multiple receptors. This is contrary to the traditional model of having a unique receptor for each unique ligand.

At least four different GPCR-linked proteins are known to respond to steroid hormones. G Protein-Coupled Receptor 30 (GPR30) binds estrogen, Membrane Progestin Receptor (mPR) binds progesterone, G Protein-Coupled Receptor Family C Group 6 Member A (GPRC6A) binds androgens, and Thyroid Hormone and Trace Amine Associated Receptor 1 (TAAR1) binds Thyroid hormone (though not technically steroid hormones, thyroid hormones can be grouped here because their receptors belong to the nuclear receptor superfamily). As an example of the effects of these GPCR-linked proteins consider GPR30. GPR30 binds estrogen, and upon binding estrogen this pathway activates adenylyl cyclase and epidermal growth factor receptor. It results in vasodilation, renoprotection, mammary gland development, etc.

Sulfated steroids and bile acids are also detected by vomeronasal receptors, specifically the V1 family.

Ion channels
Neuroactive steroids bind to and modulate the activity of several ion channels including the GABAA,   NMDA, and sigma receptors.

The steroid progesterone has been found to modulate the activity of CatSper (cation channels of sperm) voltage-gated Ca2+ channels. Since eggs release progesterone, sperm may use progesterone as a homing signal to swim toward eggs (chemotaxis).

SHBG/SHBG-R complex
Sex hormone-binding globulin (SHBG) is thought to mainly function as a transporter and reservoir for the estradiol and testosterone sex hormones. However it has also been demonstrated that SHBG can bind to a cell surface receptor (SHBG-R). The SHBG-R has not been completely characterized. A subset of steroids are able to bind to the SHBG/SHBG-R complex resulting in an activation of adenylyl cyclase and synthesis of the cAMP second messenger. Hence the SHBG/SHBG-R complex appears to act as a transmembrane steroid receptor that is capable of transmitting signals to the interior of cells.

title: Steroid hormone receptor


text:
Super Harvard Architecture Single-Chip Computer

The Super Harvard Architecture Single-Chip Computer (SHARC) is a high performance floating-point and fixed-point DSP from Analog Devices. SHARC is used in a variety of signal processing applications ranging from audio processing, to single-CPU guided artillery shells to 1000-CPU over-the-horizon radar processing computers. The original design dates to about January 1994.

SHARC processors are typically intended to have a good number of serial links to other SHARC processors nearby, to be used as a low-cost alternative to SMP.

Architecture
The SHARC is a Harvard architecture word-addressed VLIW processor; it knows nothing of 8-bit or 16-bit values since each address is used to point to a whole 32-bit word, not just an octet. It is thus neither little-endian nor big-endian, though a compiler may use either convention if it implements 64-bit data and/or some way to pack multiple 8-bit or 16-bit values into a single 32-bit word. In C, the characters are 32-bit as they are the smallest addressable words by standard.

The word size is 48-bit for instructions, 32-bit for integers and normal floating-point, and 40-bit for extended floating-point. Code and data are normally fetched from on-chip memory, which the user must split into regions of different word sizes as desired. Small data types may be stored in wider memory, simply wasting the extra space. A system that does not use 40-bit extended floating-point might divide the on-chip memory into two sections, a 48-bit one for code and a 32-bit one for everything else. Most memory-related CPU instructions can not access all the bits of 48-bit memory, but a special 48-bit register is provided for this purpose. The special 48-bit register may be accessed as a pair of smaller registers, allowing movement to and from the normal registers.

Off-chip memory can be used with the SHARC. This memory can only be configured for one single size. If the off-chip memory is configured as 32-bit words to avoid waste, then only the on-chip memory may be used for code execution and extended floating-point. Operating systems may use overlays to work around this problem, transferring 48-bit data to on-chip memory as needed for execution. A DMA engine is provided for this. True paging is impossible without an external MMU.

The SHARC has a 32-bit word-addressed address space. Depending on word size this is 16 GB, 20 GB, or 24 GB (using the common definition of an 8-bit "byte").

SHARC instructions may contain a 32-bit immediate operand. Instructions without this operand are generally able to perform two or more operations simultaneously. Many instructions are conditional, and may be preceded with "if condition " in the assembly language. There are a number of condition choices, similar to the choices provided by the x86 flags register.

There are two delay slots. After a jump, two instructions following the jump will normally be executed.

The SHARC processor has built-in support for loop control. Up to 6 levels may be used, avoiding the need for normal branching instructions and the normal bookkeeping related to loop exit.

The SHARC has two full sets of general-purpose registers. Code can instantly switch between them, allowing for fast context switches between an application and an OS or between two threads.


text:
Intergang

Intergang is a fictional organized crime syndicate appearing in American comic books published by DC Comics. Armed with technology supplied by the villainous New Gods of the planet Apokolips, they consistently appear as enemies of various DC superheroes.

Intergang appears in the TV series Lois & Clark: The New Adventures of Superman, Supergirl, Superman & Lois, the cartoons Superman: The Animated Series, Young Justice, and My Adventures with Superman as well as the DC Extended Universe film Black Adam (2022).

Publication history
Intergang first appeared in Superman's Pal Jimmy Olsen #133 (October 1970) and was created by Jack Kirby. Members of Intergang were first shown in the first issue of Kirby's Forever People in 1971.

Pre-Crisis
Intergang was founded in the 1920s by a gangster, Moxie "Boss" Mannheim, who was later killed by rivals. It was then revived by Morgan Edge and run by Boss Moxie's son Bruno "Ugly" Mannheim. Bruno was, however, getting orders and weaponry from Darkseid, who was using Intergang to help track down the Anti-Life Equation.

Morgan Edge was the head of the Galaxy Broadcasting System television network (which had recently purchased the Daily Planet and had Clark Kent transferred to its Metropolis affiliate WGBS-TV as its anchorman). It was later revealed that this was not the real Morgan Edge, but a clone from the "Evil Factory". When the clone could not bring itself to kill the original Edge at the order of Darkseid, the real Edge was imprisoned. The original Edge would later escape with the help of Jimmy Olsen. During an ensuing battle with Intergang, the clone was mistaken for the original by Intergang hitman Tombstone Gear and incinerated. The real Edge was soon free to resume his role as Galaxy's president.

Following the clone's death, different Intergang members had to run Intergang in Edge's absence. Joe Danton was the first to run Intergang and he was later killed by a car bomb. Then Max Danner became the new Intergang leader. He led Intergang in some criminal activities until he got apprehended. Clark Kent appeared as a key witness until he had to briefly leave to rescue Mr. Xavier. The outcome of the trial was not shown. When Intergang was dissolved, SKULL took over their territories. When a SKULL assassin was sent after Intergang crime boss Samuel Simeon, he was saved by Superman, though he was later apprehended by Superman trying to start a new mob outside of Metropolis.

Post-Crisis
In the Post-Crisis DC Universe, Morgan Edge was the leader of Intergang, until he suffered a heart attack due to stress. While he believed he was working for Darkseid, his Apokoliptian contact was actually DeSaad, whose only aim in supplying him with weaponry was to cause suffering. While he was in the hospital his legitimate businesses were taken over by his father Vincent Edge, and Intergang was taken over by Bruno "Ugly" Mannheim, who trained on Apokolips with Granny Goodness. A later retcon has it that Mannheim was the original leader of Intergang, dealing knowingly with DeSaad. How Edge took over is unrevealed.

Eventually, Intergang was brought down by Clark Kent and Cat Grant, Mannheim was arrested, but managed to escape. He attempted to disappear through a "Boom Tube" (a New Gods transporter), but it collapsed when he was halfway through.

Some time later, Mannheim's father "Boss" Moxie Mannheim, a gangster who had been in prison since the 1940s after being captured by the Newsboy Legion, was released. Discovering that the Newsboys were, seemingly, the same age as when he first fought them, he determined to find out how such a thing could be. Meeting renegade Project Cadmus geneticist Dabney Donovan, he arranged for himself and his dead gang members from the 1940s to be cloned into youthful bodies with superpowers which involved Dabney having to do some grave robbing. This led to his henchmen Ginny "Torcher" McCree, Mike "Machine" Gun, Noose, and Rough House being cloned and receiving superpowers. Using Vincent Edge to arrange a meeting between Metropolis' gang-leaders, an older clone of Moxie exploded enough to kill them all with Noose killing Vincent Edge. As Dabney Donovan went to look for fresh DNA samples to make use of, Moxie declared himself the new head of Intergang. The new Intergang spent much of their time tracking down Jimmy Olsen, whom Moxie believed knew Superman's secret identity.

Following a short-lived attempt by Morgan Edge to regain control, Lex Luthor gained control of Intergang, retaining Moxie as a figurehead. Moxie and his remaining lieutenants were later captured by Superman. When last seen, Intergang was run by a criminal cyberneticist named Frank Sixty.

Intergang is later seen in Metropolis robbing a bank during the Justice League's absence, only to be stopped and beaten by the Avengers.

Infinite Crisis
There was some suggestion that Boss Moxie (who was a member of the Secret Society of Super Villains at the time) was slain during the miniseries Infinite Crisis. The suggestion comes from a sequence during the Battle of Metropolisuring which Superboy-Prime snaps a villain's neck, killing him. In an interview DC editor-in-chief Dan DiDio confirmed that Boss Moxie did indeed die in Infinite Crisis #7 by stating that Superboy-Prime snapped his neck.

52
In the pages of 52, Intergang members Noose and Rough House visit Kahndaq and offer Adrianna Tomaz as tribute to Black Adam in exchange for safe passage for their group's smuggling activity. Both of them are killed by Black Adam.

In week 9, Question tells Renee Montoya that Intergang is preparing for an invasion of Gotham City. Two weeks later, the pair finally have a confrontation with the two operatives of Intergang in Gotham, Whisper A'Daire and Kyle Abbot, known in the public eye as the manager of HSC International Banking, an holding connected to Intergang itself, and her bodyguard. In the weeks that follow, the further investigations of Montoya and the Question reveal Intergang to be operating a mining company called Ridge Ferrick in regions such as Australia, and also having expanded into nations such as Oolong Island, Bialya, and Yemen, reorganized along quasi-religious lines, complete with a "holy" text known variously as the Book of Crime or the Crime Bible, which treats Cain as a heroic, if not semi-divine, figure for his role according to Judeo-Christian theology in creating the "most sacred" crime of murder. It has even been revealed that the original text is bound by the stone with which Cain slew Abel. In issue #25, Bruno Mannheim was revealed as the current head of Intergang, which is also behind the kidnapping of many of the world's "mad scientists", in a grand plan to take over America by the end of the year. He shows himself now acting like a cult leader, exalting the power of crime as the dominant order in the 21st century, and now becoming a cannibal, eating anyone he kills who refuses to join Intergang. At the same time, Magpie and Ventriloquist swear their allegiance to Intergang.

Bruno "Ugly" Mannheim returns as a giant wielding alien technology, claiming that someone other than Darkseid is behind Intergang's current activities.

Gotham Underground
In the storyline Gotham Underground, Intergang is in a gang war with Tobias Whale. Intergang buys him out and makes Tobias Whale the CEO of Kord Enterprises which has become a front for Intergang's criminal activities.

The New 52
In 2011, The New 52 rebooted the DC universe. Gotham City has fallen to Intergang's Religion of Crime branch. During a gunfight between his gang and the police, Mister Untouchable claimed that Intergang has cut him out of the action occurring in Metropolis by selling the location of their meth laboratory to the law enforcement.

Attackers from Intergang ambush Lois Lane and Jon Kent when she was driving him home from school. They run Lois' car off the road and into the woods. While Jon knocks out one of the attackers, Lois contacts Superman who defeats the attackers. Later at their barn, Lois and Clark figure out that their attackers are from Intergang and had followed Lois from her meeting with Cora Benning suspecting that she is "Author X". Bruno Mannheim was informed by two of his men that the attack on "Author X" has failed. He throws the two men into the swimming pool and electrifies it. Lois and Jon later visit Cora Benning's office and find a note stating that she was taken by Intergang. While leaving the office, the three of them encounter Bruno Mannheim in the hall who claims that he is asking for directions. Lois thinks to herself that Mannheim is trying to get her to lower her guard. When Lois goes to pick up Jon from school and finds him in the library, they are ambushed by Intergang agents who then trap them in a tool closet which they set on fire. Jon's superpowers manifest as he manages to break down the door. When Jon gets Lois out of the burning tool closet, they are then surrounded by Intergang thugs. Breaking off his fight with Blackrock, Superman manages to save Lois and Jon as the Intergang thugs are caught in the explosion.

Membership
Here is the known membership of Intergang:

Leaders

 * Moxie Mannheim - First leader of Intergang and the father of Bruno Mannheim. Known as "Boss Moxie".
 * Morgan Edge - Second leader of Intergang and the son of Vincent Edge.
 * Vincent Edge - Third leader of Intergang and the father of Morgan Edge.
 * Bruno Mannheim - Fourth and current leader of Intergang and the son of Moxie Mannheim. He was later retconned as the original leader of Intergang.
 * Lex Luthor - Fifth leader of Intergang.
 * Frank Sixty - A cyborg who is the sixth leader of Intergang.
 * Darkseid - The benefactor of Intergang.

Other members

 * Alistair Bendel-White - A fixer.
 * Aku Kwesi - A criminal who was responsible for murdering Vixen's mother.
 * Blackrock - Bradley Glenn with the Blackrock armor granting him super strength and leaping ability.
 * Chiller - Pale assassin and former member of the 1000 gang who is a foe of Booster Gold.
 * Dabney Donovan - A mad scientist that worked for Project Cadmus.
 * Doctor Moon -
 * Doctor Polaris -
 * Doctor Sivana -
 * Gillespie -
 * Ginny "Torcher" McCree - A pyrokinetic operative of Intergang and girlfriend of Mike "Machine" Gunn who Dabney Donovan cloned from one of Moxie's original henchmen. She later committed suicide following the death of one of Mike "Machine" Gunn's clones.
 * Hellgrammite -
 * Joe Danton - An Intergang operative who was a short-time leader following the death of Morgan Edge's clone. He was killed by a car bomb.
 * Johnny "Stitches" Denetto - A crime boss who had his face peeled off by Tobias Whale back when he used to work for him. Desaad sewed a new face onto him which was made from dead humans and animals.
 * Key -
 * Kyle Abbot - An operative for Ra's al Ghul who can turn into a wolf and a werewolf-like creature. Normally paired with Whisper A'Daire.
 * Magpie -
 * Mantis -
 * Mari Nichol - The daughter of the second Doctor Polaris.
 * Max Danner - An Intergang operative who become leader following Joe Danton's death.
 * Mike "Machine" Gunn - An operative of Intergang and boyfriend of Ginny "Torcher" McCree who Dabney Donovan cloned from one of Moxie's original henchmen. He can shape his hands into guns that can fire bone bullets. There were extra clones of Mike made when one of them ends up killed. One clone of Mike was later killed during a jailbreak.
 * Neutron -
 * Noose - An operative of Intergang who Dabney Donovan cloned from one of Moxie's original henchmen. He can extend his fingers to give them a tentacled appearance. He was later killed by Black Adam.
 * Parademons -
 * Pestilence - Member of the Four Horsemen of Apokolips.
 * Prankster -
 * Radion - A henchman with irradiated powers.
 * Rough House - A super-strong operative of Intergang who Dabney Donovan cloned from one of Moxie's original henchmen. He was later killed by Black Adam.
 * Samuel Simeon - An Intergang crime boss who Superman saved from an assassin sent by SKULL.
 * Shockwave - Chicago supervillain for hire named Arnold Pruett.
 * Steel Hand - An Intergang mobster with a prosthetic right hand made of steel. He was responsible for using a sniper to murder Thaddeus Brown before being brought to justice by Mister Miracle.
 * Thaddeus Killgrave - A mad scientist with dwarfism who worked for Intergang.
 * Tobias Whale - He ended up bought out by Intergang and made the CEO of Kord Industries to serve as a front for Intergang's activities.
 * Torque - Dudley Soames is a detective from the Blüdhaven Police Department who was secretly on Blockbuster II's side. His head was twisted 180 degrees by Blockbuster II for crossing him yet survived. Due to his head remaining at this angle, Torque uses mirrored glasses to see forward which allowed him to see all 360 degrees of the battlefield.
 * Toyman -
 * Ventriloquist -
 * War - Member of the Four Horsemen of Apokolips.
 * Whisper A'Daire - An operative for Ra's al Ghul who can turn into a snake or a half-snake creature. Normally paired with Kyle Abbott.

Other versions
A possible future incarnation of Intergang appears in "Armageddon 2001", in which they take Metropolis hostage with a nuclear bomb. However, one of their members grows nervous and detonates it too early, leading to several deaths, such as Lois Lane's, and Superman destroying every nuclear weapon on Earth.

Television

 * Intergang appears in Lois & Clark: The New Adventures of Superman, led by Bill Church Sr., his wife Mindy, and his son Bill Church Jr. of Multiworld Communications. This version of the group is not involved with Apokolips.
 * Intergang appears in Superman: The Animated Series, initially led by Bruno Mannheim until he is killed while preparing Earth for Darkseid's invasion and Granny Goodness takes over leadership.
 * Intergang appears in the Smallville episode "Stiletto", initially led by Ron Milano, head of the Ace o' Clubs, before Bruno Mannheim kills him and takes over leadership. Additionally, Mr. Freeze and Prankster appear as Intergang members in the comic book continuation Smallville Season 11.
 * Intergang appears in Young Justice, led by Bruno Mannheim and consisting of Whisper A'Daire, Scorpia A'Daire, and Cairo DeFrey.
 * Intergang appears in the Supergirl episode "Dream Weaver". They collaborate with Wyatt Kote, warden of Van Kull Prison, to use its alien prisoners to commit illegal activities under the cover of a work release program. However, Supergirl and Martian Manhunter foil the scheme, with Kote being arrested and the alien prisoners involved receiving commuted sentences.
 * Intergang appears in Superman & Lois, consisting of Boss Moxie, Bruno Mannheim, Thaddeus Killgrave, Elias Orr, Aleister Hook, Mike Gunn, James Distefano, and Peia Mannheim. In the episode "Haywire", Intergang breaks Killgrave out of a prison transport so he can seek revenge on Superman, only to be defeated by him and re-apprehended by the Department of Defense (DOD). In the third season, Mannheim leads Intergang in conducting revival experiments involving corpses such as Atom Man and Bizarro's, X-Kryptonite, and Superman's blood samples.
 * Intergang appears in My Adventures with Superman, led by Silver Banshee and consisting of Rough House and Mist.

Film

 * Intergang appears in the DC Animated Movie Universe (DCAMU) films The Death of Superman and Reign of the Supermen.
 * Intergang appears in Black Adam. This version of the group is an international crime syndicate, with its Kahndaq sect led by the militant Ishmael Gregor, who seeks to rule Kahndaq via Sabbac's demonic power and the Crown of Sabbac.

Video games
Intergang appears in DC Universe Online, with Bruno Mannheim, Whisper A'Daire, and Kyle Abbot as prominent members.

Miscellaneous
Intergang appears in the Arrowverse tie-in comic Earth-Prime #2, consisting of Bruno Mannheim, Barrage, Hi-Tech, Loophole, Thaddeus Killgrave, Sleez, and Terra-Man.

title: Intergang


text:
Uppsala öd

Uppsala öd, Old Norse: Uppsala auðr or Uppsala øðr (Uppsala domains or wealth of Uppsala) was the name given to the collection of estates which was the property of the Swedish Crown in medieval Sweden. Its purpose was to finance the Swedish king, originally the "king of Uppsala", and they supported the king and his retinue while he travelled through the country. There was one estate of this kind in most hundreds and it was usually called Husaby. It was the home of the king's tax collector, and it was at the local estate of Uppsala öd that the people of the hundred delivered the taxes in form of goods. The estates were most common in Svealand.

Its origins are prehistoric and unknown, but according to a tradition documented by the thirteenth-century historian Snorri Sturluson it originated as a donation given by the god Freyr to the Temple at Uppsala which he founded.

It was stated in the Swedish medieval laws that Uppsala öd was to follow the royal institution intact without any lost property. The full extent of Uppsala öd is unknown, but individual estates are enumerated in the Law of Hälsingland and in the younger Westrogothic law.

However, during the thirteenth century, the system became obsolete for the king and then many of the estates passed to the nobility and the church, in spite of the laws that forbade any diminution of the property. The reasons for this was that the king's subjects began to pay monetary taxes.

Uppsala öd was the first documented pieces of what would become Swedish State property.

A selection of estates belonging to Uppsala öd

 * Gamla Uppsala
 * Husby at Vendel
 * Fornsigtuna
 * Husaby
 * Ränninge on Fogdö
 * Hovgården on Adelsö

title: Uppsala öd


text:
File:Siwucha.jpg

A bottle of Siwucha, from the producer website. Fair use assumed.

Rationale for use in Siwucha vodka

 * To illustrate the subject of the article, including logos and trade dress etc., as these elements are inherently copyright and cannot be replaced with free imagery. While a free image could be taken of the bottle and packaging, such an image would remain subject to copyright and it is in any case questionable whether copyright subsists in the photograph as distinct from the bottle and packaging.
 * The image is used as the primary means of identification of the main subject of the article.
 * The copyright holder is Luksusowa, the producer.
 * The image used is low-resolution and is unlikely to compete with the copyright holder's usage of the packaging, which is to market the drink.

title: File:Siwucha.jpg


text:
User talk:Schweppes42

Hi., just letting you know I listed your on requests for Arbitration, Requests_for_arbitration with the following complaint "User:Reithy has a request for comments open: Wikipedia:Requests_for_comment/Reithy detailing his vandalism spree and his attack on other users. Since this every single day he has been creating a new account to insult me on his user/page talks pages, Talk about what a vandal I i'm, Revert other editors edits with his different accounts to make it seem like he has concenus. etc...(please see request for comments for basis for major problems.

He has been conducting a general campaign against me in the past week, with a different account per day to make it seem as if I have a large base of hatred from different users being directed at how awful I am.

Impossible to talk/reason with because he actually seems to like to believe that he's a sockpuppet and a unique indivudal any time you try to confront him.

His accounts he has created in just the past week are: User:Chuckschneider User:Schweppes42 User:144.132.89.151 user:Guido1970 user:ReithySockPuppet (pay particular attention to this one's user page) User:Lukewilson user:CorporalPunishment user:MunchieRonnie and user:PockyChoc."

please respond if you wish to. Chuck F 08:55, 19 Oct 2004 (UTC)

title: User talk:Schweppes42


text: User talk:144.132.89.151

title: User talk:144.132.89.151