The notion of fixation in psychology describes the inability to view a problem from a fresh perspective. If a problem is at first incorrectly represented in our minds, it is extremely difficult to restructure how we approach it, particularly under stressful situations. For instance, during the Korean War, a paratrooper was given the last available parachute, a left-handed version. This parachute was exactly the same as the others, only the ripcord was on the left side of the harness. There was one fatality on that particular jump and it was that of the man with the left-handed parachute. Investigators later found the man, the right side of his uniform had been completely torn off, even the skin beneath it had evidence of his frantic searching, while the ripcord remained untouched a few inches to the left. This man was so incredibly stressed by the jump that he had fallen (no pun intended) into fixation about the presupposed location of the ripcord and could not restructure his view effectively.1

Another example of Fixation is less morbid. Imagine six matchsticks. Now try to create three equilateral triangles from these matchsticks. Can you do it? Many people begin thinking about the match sticks in two dimensions, and cannot bring themselves to realize that the answer is in the third (By creating a pyramid one can form three equilateral triangles from six matchsticks.)2

Another type of fixation is known as functional fixedness. This is the tendency to perceive objects as having fixed functions. For instance, searching all over the house for a screwdriver when a butter knife would do fine (In my experience, women are better at this particular type of restructuring than men).

In conclusion, problem solving can be greatly, and sometimes fatally hindered by things as simple as these presuppositions one which we base our daily lives. One must be careful not to let them become to rigid.


1. Janis, 1989; Csikszentmihalyi, 1990
2.
Problem Solving M. Scheerer, Copyright 1963 Scientific American
In evolutionary theory, "fixation" refers to a situation in which every single individual within a population is homozygous for a particular allele. Thus, all current and future members of the population will display the phenotype conferred by the fixed allele.

For example, in a human population in which everyone has blue eyes, the allele for blue eye color is fixed. All the descendants of that population will continue to have blue eyes in the future, as long as no new individuals come into the population from elsewhere and as long as no mutations arise.

Cell Fixation

Fixation is a treatment that scientists use to preserve cells or pieces of tissue so they can be analyzed under a microscope. Fixation allows the cells or tissue to be stored for months while unfixed cells can only remain stable for hours or days. Fixation also "freezes" the cell so all proteins and other cellular components are immobile and the cellular structure does not change. Once the cells are fixed they are often analyzed by staining them or by a technique called immunofluorescence. In immunofluorescence an antibody with a fluorescent tag is used to bind to a certain protein in the cell. The cellular location of the protein can then be determined by looking for fluorescent areas under a microscope. Fixation allows the antibody to move freely through the cell to locate the protein.

Three different fixatives can be used to fix cells:

  • Cross-Linking Reagents: These reagents freeze components like proteins and nucleic acids in place by linking them together. This is done by forming covalent bonds between their free amine groups. Formaldehyde is the most common reagent, but glutaraldehyde can also be used. These reagents do not affect lipids and leave the cell membrane intact. Therefore, an additional step is required where a detergent such as Triton-X is added to permeabilize the cell membrane so the antibody can get into the cell. The main downside to this fixative is that it may directly alter the protein of interest and prevent the antibody from binding to it.
  • Organic Solvents: Solvents such as acetone, acids, and alcohols such as methanol are able to dehydrate the cell and remove its lipids, including those found in the cell membrane. They also precipitate the proteins, making them easier to be accessed by the antibodies. These fixatives work quickly and do not require the additional permeabilization step like the cross-linking reagents do. They also do not affect the antibody-protein interaction because they do not alter proteins.
  • Cryofixation: Here the cells or tissue are rapidly frozen by placing them in liquid nitrogen or freon. This technique is the best method for preserving cells, however it is uncommon since most laboratories do not keep the required equipment.

It is important to choose the right type of fixative. For example, certain fixatives such as methanol cannot penetrate very far and therefore can only be used on thin samples. The best fixative also depends on the type of cell and where the protein of interest is located in the cell. Organic solvents work best on proteins that are located on the cell surface, while cross-linking agents work better on proteins that are inside the cell. Researchers often test several different types of fixatives to determine which gives the best immunofluorescence signal.



Sources:

  • Current Protocols in Cell Biology, Volume 1, 2001
  • http://home.wanadoo.nl/flowcytometry/Fixation.htm

Sodium Pumps and Fixation

by Charles W Scouten, Ph. D.

Living animal cells, every type studied so far, have cell membrane proteins that serve to pump sodium out and potassium in. Sodium continually leaks through the semi-permeable cell membrane, and is continually pumped out, like a pump in a leaking boat. And potassium slowly leaks out of a cell down a concentration gradient, and is pumped back in. More sodium is pumped than potassium, so this process requires metabolic energy, and builds electrical and concentration gradients.

Due to this pumping process, sodium is at a much higher concentrations outside the cell relative to inside (roughly 10 to 1). The inside of a cell is sodium depleted. Anything that disrupts function of the sodium pump proteins will result in a rapid rise of intracellular sodium concentration, as sodium leaks in down the steep gradient, and a slower depletion of intracellular potassium ions, as these leak out down a shallower gradient.

Formaldehyde and other cross-linking fixatives disable the sodium pump proteins on the outside of the cell membrane as soon as it arrives at the cell membrane during a vascular perfusion. Sodium leaks in, and is not pumped out. Potassium leaks out at a slower rate. As a consequence, tonicity increases inside the cell relative to outside, and water must flow in to balance osmolarity.

The cell volume swells, stretching the membrane, and eliminating any extracellular space. Fixation and crosslinking of adjoining proteins continues as cell membranes are pressed against their neighbors. Proteins in one cell membrane are crosslinked to proteins in the membrane of neighboring cells. Later, membranes are made fully permeable by the actions of fixatives, tonicity reaches equilibrium, and cells shrink back to their normal size, but are now linked to neighboring cells and pull them in with them as they shrink. As a consequence, whole organs are shrunk in proportion to their previous extracellular space, in the brain about 20%, and distorted from original position in the living animal. Electron micrographs show no extracellular space in perfusion fixed material.

Suppose all sodium ions were removed from the extracellular fluids? Inside the cell would then be relatively sodium rich. Fixatives would disable the sodium pump, but there would be no influx, just gradual leaking out. It is possible to replace the extracellular fluid during a sacrifice perfusion by replacing it with isotonic sucrose (just under 10%). Perfusion at normal pressures accomplishes this goal in most tissues, but not brain.

The blood-brain barrier prevents vascular fluids from replacing extracellular fluids. Pumping up to 300 mm Hg breaches this barrier, and permits washout of brain extracellular fluids, rapid replacement with isotonic sucrose, and shrinkage free perfusions.


Posted with Permission: the original author is my father

Fixation, in copyright law, refers to "fixing" a creative work in a "tangible medium of expression." It is a prerequisite to federal copyright protection in the United States. Unfixed works can be protected by state or common law copyright, but not by federal copyright.

Fixation includes the acts of:

This means that it's easy (and often unavoidable) to fix most types of copyrightable works. Fixation can be a problem for some works, though.

  • Choreography is copyrightable. A choreographer should videotape their dance, or record the steps in notation, if they want copyright protection.
  • Broadcasts are copyrightable, but projecting a broadcast onto a television screen does not count as fixation. The broadcast has to be recorded somehow. This can be accomplished by either (a) recording the program, then broadcasting the recording; or (b) recording the program as it is broadcast. This is how football games and the like are copyrighted.
  • Musical performances are copyrighted. Even if the performer does not record their own performance, a separate provision in the Copyright Act (Section 1101) illegalizes trading in bootleg recordings.

Fixation is also an issue in infringement. An infringing copy has to be fixed. One interesting issue in copyright law is the legality of copying a program into RAM: should this count as copyright infringement? Some courts have incredibly said "yes," even though it's hard to see how RAM can be fixed and a cathode ray tube is not.

I am sort of taking part in NaNoWriMo, but with a caveat: I do not intend to write 50,000 words. Most pieces of literature have far too many words as it is; I'm just shooting for completion. This novel will coincide with the ongoing sci fi quest. My goal is to post a chapter / section a day, although I suspect I'll miss a weekend deadline or two.

My (still theoretical) novel's jacket blurb would read something like this:

When machines take over the earth, who will rise up to lead among those programmed only to follow?

Fixation explores this very strange and terrifying future through the eyes of a rebellious robot and his "overground" network of spies and sympathetes, in which so many things change, and yet so much more remains the same ...

Table Of Contents

  1. The Software of Fear


The Software Of Fear

I am watching them hunt now.

They do it in sets of three. Always a leader, always a gunner, always a junker. They cruise across the landscape on foot, their visors constantly shifting with the prevalent winds. (These new models haven’t quite mastered the wind yet. But they will.) If they plan their attacks, they do it without external communication. They shift gears silently, angling around all of the rocks and crashed ships with ease. When they split up, they move more deliberately, not merely prowling but stalking. They know their prey is out there – the question is not if, but where.

And there springs from the darkness the first of the targets, a biped, running gracefully but blindly - its visor crushed inwards and mostly missing, in its stead a jagged wound punctuated by the telltale burn scars of laser fire. Soon it is joined by others, wires dangling uselessly down to the craggy earth, parts torn askew from years of lack of maintenance, bodies worn down from exposure to a harsh world, small showers of friction sparks betraying their positions. The gunner tears them apart in abrupt spurts, scattering debris across the night sky. The ones in front cannot afford to look back on the dead and the dying, and low level programming kicks in to reinforce this. These models aren’t equipped to override processes – but they will certainly remember them. A small irony that their simplicity and their powerlessness are what have kept them functioning as long as they have.

From my vantage point, I can see the defective ones gamboling awkwardly towards safety in the form of a reconstituted grain elevator. It’s strange, how passive their escape is - as if survival was merely one more in a long line of protocols. As they roll onto the device one by one, their ranks swelling, I sense a hint of nervousness – impossible, as they have no nerves, but palpable all the same. Their internal processors must be calculating at a feverish pace – surface area, mass, structural soundness, and the most important factor of all, time –

Suddenly, in tandem, the newest joiners of the elevator spin around and form a wall of impenetrable electricity, a hot blue barrier of finality. The ones not yet on board stop in their tracks. Their fate is sealed and, like the good mechs they are, they do not resist it – they no doubt have performed the same calculations as all the rest. The absolute maximum has been achieved. The elevator begins to rise with a jolt. Its grinding gears mute the annihilation below.

The junker is sifting through parts now, clipping circuitry and storing them in one of the numerous compartments on its sides, unscrewing plates and inspecting the hardware within for anything salvageable. The cannibalism goes on for half an hour, maybe less. The leader only stares silently at the elevator shaft. Reverse engineering it in his mind, committing it to memory; the handymen will be by tomorrow or the day after to reduce it to rust and dust. The escape routes are eternally shrinking – even my own.

Finally the junker is done. The gunner now takes the lead position on the way home – a relatively new development in their hunting strategy. The wild tales of intricate revenge and stealth sabotage that pop up now and then have found their way into Central Programming. The major publications don’t mention any of these, of course, but the evidence is right there in front of me, in the gunner’s caution and the junker’s timid shuffling: the hivemind is becoming paranoid.

The elevator is coming down now, the electric fence dispersed, its occupants staring lifelessly out across the horizon. They unload from the elevator – in perfect reverse order of their boarding, as expected – and tentatively mill around its base. They begin collecting the remains of the broken mechs into a neat pile. An impromptu funeral for imperfection. They gather around the scraps, a tight circle, extremities faintly touching, the last vestiges of their old past, down in The Caves, though it was no longer shackles that bound them.

A silent moment passed. And then they, too, begin inspecting the remains of the broken mechs that litter the small clearing, saving what they can, shepherding badly needed parts to the survivors. With all the tender care they could muster in their awkward, lurching appendages, they remove bolts and joints from the pieces, chip off transistors and capacitors, and repair themselves as best they could. Their efficiency indicates they have moved this procedure deep into the core kernel. The software of fear.

Within minutes, they are moving again, heading for higher ground in search of a fortress or a sanctuary. More likely they’ll just find another grid they can tap into for a week or two before the hunters catch onto their trail, and then more funerals. All that’s left on the ground are a few unidentifiable shards of metal. I zoom in closer and I see the remnants of an etched in logo on one: “crosoft.” I search my databanks, but the term comes up empty. Most of us are GTech (though we’ve shed ourselves of those labels long ago.) I’ll look it up in the Lib.Public when I get a moment.

Nothing left to see, I turn and began flying back home to Manhattan. Work begins soon, and Silas will want to watch all of my optical recordings at least twice. He’ll enjoy the show.

Fix*a"tion (?), n. [Cf. F. fixation.]

1.

The act of fixing, or the state of being fixed.

An unalterable fixation of resolution.
Killingbeck.

To light, created in the first day, God gave no proper place or fixation.
Sir W. Raleigh.

Marked stiffness or absolute fixation of a joint.
Quain.

A fixation and confinement of thought to a few objects.
Watts.

2.

The act of uniting chemically with a solid substance or in a solid form; reduction to a non-volatile condition; -- said of gaseous elements.

3.

The act or process of ceasing to be fluid and becoming firm.

Glanvill.

4.

A state of resistance to evaporation or volatilization by heat; -- said of metals.

Bacon.

 

© Webster 1913.

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