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Physical

Specialty Definition: Physical

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Specialty Definition: Body

(From Wikipedia, the free Encyclopedia)

With regard to living things, a body is the integral physical material of an individual, and contrasts with soul, personality and behavior. In some contexts, a superficial element of a body, such as hair may be regarded as not a part of it, even while attached. The same is true of excretable substances, such as stool, both while residing in the body and afterwards. Plants composed of more than one biological cell are not normally regarded as possessing a body.

"Body" often is used in connection with appearance, health issues and death. The body of a dead person is also called a corpse (human) or cadaver. The dead bodies of vertebrate animals and insects are sometimes called carcasses.

The human body consists of a head, neck, trunk, two arms, two legs and the genitals of the groin, which differ between males and females.

The study of the working of a body is anatomy.

A body is also a held-together collection or group of physical objects or abstract ideas, and in particular an organisation. The whole is of more than the sum of the individual members.

See Also

• Emergence

  Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Body."

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Physical chemistry

(From Wikipedia, the free Encyclopedia)

Physical chemistry is a science field in the crossover between chemistry and physics. Chemical thermodynamics, chemical kinetics , quantum chemistry, statistical mechanics, and spectroscopy are some areas of chemistry comprising the bulk of physical chemistry.

Physical chemistry is also strongly intertwined in the pursuit of materials science.

Important Physical-chemists

• Peter Debye
• J.W. Gibbs
• J.H. van 't Hoff
• B. Težak

Literature

• Physical Chemistry, P.W. Atkins, 1978, Oxford University Press
• Introduction to Modern Colloid Science, R.J. Hunter, 1993, Oxford University Press
• Principles of Colloid and Surface Chemistry, P.C. Hiemenz, R. Rajagopalan, 1997, Marcel Dekker Inc., New York

  Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Physical chemistry."

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Physical constant

(From Wikipedia, the free Encyclopedia)

In science, a physical constant is a physical quantity whose numerical value is fixed. It can be constrasted to a mathematical constant which is a fixed number that does not directly involve a physical measurement.

There are many such constants used in science, some of the most famous of which being: Planck's constant, the gravitational constant and Avogadro's constant (better known as Avogadro's number). Constants can take many forms; some, such as the Planck length represents a fundamental physical distance, others such as the speed of light signifies the maximun speed limit of the universe, yet others are dimensionless quantities such as the fine-structure constant which embodies the interaction between electrons and photons.

Below is a list of physical constants:

Quantity	Symbol	Value	Ref.
speed of light in vacuum	c	299 792 458 m·s-1 (defined)	a
permeability of vacuum	μ0	4π × 10-7 N A-2 (defined)	a
		12.566 370 614... × 10-7 N A-2	a
permittivity of vacuum	ε0 = 1/(μ0c2)	8.854 187 817 ... × 10-12 F·m-1	a
characteristic impedance of vacuum	Z0 = μ0c	376.730 313 461... Ω (defined)	a
gravitational constant	G	6.672 59(85) × 10-11 m3·kg-1·s-2	?
Planck's constant	h	6.626 068 76(52) × 10-34 J·s	a
Dirac's constant	h = h / (2π)	1.054 571 596(82) × 10-34 J·s	a
Planck mass	mp = (hc / G)1/2	2.1767(16) × 10-8 kg	a
Planck length	lp= (hG / c3) 1/2	1.6160(12) × 10-35 m	a
Planck time	tp = (hG / c5)1/2	5.3906(40) × 10-44 s	a
elementary charge	e	1.602 176 462(63) × 10-19 C	a
electron rest mass	me	9.109 381 88(72) × 10-31 kg	a
proton rest mass	mp	1.672 621 58(13) × 10-27 kg	a
neutron rest mass	mn	1.674 927 16(13) × 10-27 kg	a
atomic mass constant, (unified atomic mass unit)	mu = 1 u	1.660 538 73(13) × 10-27 kg	a
Avogadro's number	L, NA	6.022 141 99(47) × 1023	a
Boltzmann constant	k	1.380 6503(24) × 10-23 J·K-1	a
Faraday constant	F	9.648 534 15(39) × 104 C·mol-1	a
gas constant	R	8.314 472(15) J·K-1·mol-1	a
zero of the Celsius scale		273.15 K (defined)	?
molar volume, ideal gas, p = 1 bar, θ = 00C		22.710 981(40) L·mol-1	a
standard atmosphere	atm	101 325 Pa (defined)	a
fine structure constant	α = μ0e2c / (2h)	7.297 352 533(27) × 10-3	a
	α-1	137.035 999 76(50)	a
Bohr radius	a0	5.291 772 083(19) × 10-11 m	a
Hartree energy	Eh	4.359 743 81(34) × 10-18 J	a
Rydberg constant	R∞	1.097 373 156 8549(83) × 107 m-1	a
Bohr magneton	μB	9.274 008 99(37) × 10-24 J·T-1	a
electron magnetic moment	μe	-9.284 763 62(37) × 10-24 J·T-1	a
Lande g-factor for free electron	ge	2.002 319 304 386(20)	?
nuclear magneton	μN	5.050 786 6(17) × 10-27 J·T-1	?
proton magnetic moment	μp	1.410 607 61(47) × 10-26 J·T-1	?
proton magnetogyric ratio	γp	2.675 221 28(81) × 108 s-1·T-1	?
magnetic moment of protons in H20, μ'p	μ'p / μB	1.520 993 129(17) × 10-3	?
proton resonance frequency per field in H20	γ'p / (2π)	42.576 375 (13) M·Hz·T-1	?
Stefan-Boltzmann constant	σ	5.670 400(40) × 10-8 W·m-2·K-4	a
first radiation constant	c1	3.741 774 9(22) × 10-16 W·m2	?
second radiation constant	c2	1.438 769 (12) × 10-2 m·K	?
standard acceleration of free fall	gn	9.80665 m·s-2 (defined)	?

Some "constants" are really artifacts of the unit system used, like mks or cgs. In natural units, some of these supposedly physical constants turn out to be mere conversion factors.

References

^aPeter J. Mohr and Barry N. Taylor, "CODATA Recommended Values of the Fundamental Physical Constants: 1998," Journal of Physical and Chemical Reference Data, Vol. 28, No. 6, 1999 and Reviews of Modern Physics, Vol. 72, No. 2, 2000.[[1]

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Physical constant."

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Physical law

(From Wikipedia, the free Encyclopedia)

This article is about law in science, for law as it refers to the legal system see: law

A physical law or a law of nature is a scientific generalization based on empirical observations. It is different from a theory which is a framework designed to make predictions and to explain physical laws. Laws of nature are different from legal code (see law). Legal code is the creation of man, sometimes perhaps inspired by higher beings. Laws of nature are conclusions from scientific experiments. Some of the more famous laws of nature are Isaac Newton's theories of (now) classical mechanics, presented in his Principia Mathematica and Albert Einstein's theory of relativity.

Within most fields of study, and in science in particular, the elevation of some principle of that field to the status of "law" usually takes place after a very long time during which the principle is used and tested and verified. Though in some fields of study such laws are simply postulated as a foundation and assumed.

Mathematical laws are something in between: they are often arbitrary and unproven in themselves, but they are then judged by how useful they are in making predictions about the real world.

• Examples of scientific laws include Boyle's law of gases, conservation laws, Ohm's law, the four laws of thermodynamics and others.
• Laws of other fields of study include Occam's razor as a principle of philosophy and the Pareto principle of economics.
• Examples of observed phenomena often described as laws include the Titius-Bode law of planetary positions, Zipf's law of linguistics, Moore's law of technological growth. Other laws are pragmatic and observational, such as the law of unintended consequences.

  Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Physical law."

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Physical layer

(From Wikipedia, the free Encyclopedia)

The physical layer is level one in the seven level OSI model. It performs services requested by the data link layer.

This level is referring to network hardware, physical cabling or a wireless electromagnetic connection. It also deals with electrical specifications, collision control and other low-level functions.

The physical layer is the very simplest, defining only exactly what a bit is: in other words how to transmit a one or a zero. For example, you would specify at this layer things like what shapes the electrical connectors are, what frequencies to broadcast at, and what frequencies are allowed and will not blow up the network cards. In a snail-mail network, that is a network made up of people posting letters to one another, the physical layer is all about how you write and read individual letters of the alphabet.

The major functions and services performed by the physical layer are:

• establishment and termination of a connection to a communications medium;
• participation in the process whereby the communication resources are effectively shared among multiple users, e.g., contention resolution and flow control;
• conversion between the representation of digital data in user equipment and the corresponding signals transmitted over a communications channel.

Examples

• RS-232
• ISDN
• 10BASE-T, 10BASE2, 10BASE5, 100BASE-TX, 100BASE-FX, 100BASE-T, 1000BASE-T, 1000BASE-SX are all physical layer transports for Ethernet
• electricity
• radio

  Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Physical layer."

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Physical oceanography

(From Wikipedia, the free Encyclopedia)

Physical oceanography is the study of the physical processes affecting and being driven by the Earth's oceans, including:

• ocean currents, including:
  • wind-driven surface currents [see Upwelling]
  • geostrophic currents [see Coriolis effect]
  • thermohaline circulation [see Thermohaline circulation, Global conveyor belt]
• water masses [see Water mass, North Atlantic Deep Water]
• tides [see Tide, Tidal resonance, Tidal locking]
• stability of the water column [see Density (sea water)]
• mixing and turbulence [see Fluid mechanics]

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Physical oceanography."

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Physical property

(From Wikipedia, the free Encyclopedia)

A Physical property is an aspect of an object that can be experienced using one of the five human senses: touch, taste, smell, sight or sound, or, in an extended sense, detected through any measuring device.

Properties can be isotropic or anisotropic.

In Quantum mechanics, physical properties are referred to as observables.

Physical property does not refer to land.

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Physical property."

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Physical science

(From Wikipedia, the free Encyclopedia)

Physical science is the term used to describe the branch of science including chemistry and physics, and sometimes contrasted with natural or biological science.

Physical science includes the sub-branches of aerodynamics, astronomy and astrophysics, classical mechanics, civil engineering, electrical engineering, energy, geography, mechanical engineering, physical chemistry, statistical mechanics, thermodynamics, quantum mechanics. Sometimes math is also included, though more commonly it is considered a separate science or theoretical practice. There also exist fields such as biomechanics, biochemistry, and genetics, which span the gap between the physical and biological sciences.

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Physical science."

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Physical therapy

(From Wikipedia, the free Encyclopedia)

Physical therapists provide services that help restore function, improve mobility, relieve pain, and prevent or limit permanent physical disabilities of patients suffering from injuries or disease. They restore, maintain, and promote overall fitness and health. Their patients include accident victims and individuals with disabling conditions such as low back pain, arthritis, heart disease, fractures, head injuries, and cerebral palsy.

Therapists examine patients' medical histories, then test and measure their strength, range of motion, balance and coordination, posture, muscle performance, respiration, and motor function. They also determine patients' ability to be independent and reintegrate into the community or workplace after injury or illness. Next, they develop treatment plans describing a treatment strategy, the purpose, and anticipated outcome. Physical therapist assistants, under the direction and supervision of a physical therapist, may be involved in the implementation of the treatment plan. Physical therapist aides perform routine support tasks, as directed by the therapist.

Treatment often includes exercise for patients who have been immobilized and lack flexibility, strength, or endurance. They encourage patients to use their own muscles to further increase flexibility and range of motion before finally advancing to other exercises improving strength, balance, coordination, and endurance. Their goal is to improve how an individual functions at work and home.

Physical therapists also use electrical stimulation, hot packs or cold compresses, and ultrasound to relieve pain and reduce swelling. They may use traction or deep-tissue massage to relieve pain. Therapists also teach patients to use assistive and adaptive devices such as crutches, prostheses, and wheelchairs. They may also show patients exercises to do at home to expedite their recovery.

As treatment continues, physical therapists document progress, conduct periodic examinations, and modify treatments when necessary. Such documentation is used to track the patient's progress, and identify areas requiring more or less attention.

Physical therapists often consult and practice with a variety of other professionals, such as physicians, dentists, nurses, educators, social workers, occupational therapists, speech-language pathologists, and audiologists.

Some physical therapists treat a wide range of ailments; others specialize in areas such as pediatrics, geriatrics, orthopedics, sports medicine, neurology, and cardiopulmonary physical therapy.

In the United States, experienced physical therapists can apply to take a specialty exam to earn board certification in any of seven sub-specialty areas: Cardiovascular and Pulmonary, Clinical Electrophysiologic, Geriatric, Neurologic, Orthopaedic, Pediatric, and Sports physical therapy. Therapists who have board certification will have a designation such as "OCS" (Orthopedic certified specialist) after their names. You can search a directory of accredited specialists on the APTA website: http://www.apta.org/Education/specialist/dir_cert_cln_pt-85-97

A number of physical therapists have found the Alexander Technique to be a useful tool to incorporate into their practice.

In some countries, physical therapy is known as physiotherapy.

Note: When you get to OT and RT, you will see that there are many overlaps in these fields. For example, "Hand Therapy" can be PT or OT, actually based more on a particular medical facilities' resources. But, it does fit under both definitions.

Qualifications

All States (in the United States) require physical therapists to pass a licensure exam after graduating from an accredited physical therapist educational program before they can practice.

According to the American Physical Therapy Association, there were 189 accredited physical therapist programs in 1999. Of the accredited programs, 24 offered bachelor?s degrees, 157 offered master?s degrees, and 8 offered doctoral degrees. By 2002, all physical therapist programs seeking accreditation will be required to offer degrees at the master?s degree level and above, in accordance with the Commission on Accreditation in Physical Therapy Education.

Physical therapist programs start with basic science courses such as biology, chemistry, and physics, and then introduce specialized courses such as biomechanics, neuroanatomy, human growth and development, manifestations of disease, examination techniques, and therapeutic procedures. Besides classroom and laboratory instruction, students receive supervised clinical experience. Individuals who have a 4-year degree in another field and want to be a physical therapist, should enroll in a master?s or a doctoral level physical therapist educational program.

Competition for entrance into physical therapist educational programs is very intense, so interested students should attain superior grades in high school and college, especially in science courses. Courses useful when applying to physical therapist educational programs include anatomy, biology, chemistry, social science, mathematics, and physics. Before granting admission, many professional education programs require experience as a volunteer in a physical therapy department of a hospital or clinic.

Physical therapists should have strong interpersonal skills to successfully educate patients about their physical therapy treatments. They should also be compassionate and possess a desire to help patients. Similar traits are also needed to interact with the patient?s family.

Physical therapists are expected to continue professional development by participating in continuing education courses and workshops. A number of States require continuing education to maintain licensure.

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Physical therapy."

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Physicalism

(From Wikipedia, the free Encyclopedia)

The following is a portion of Larrys Text; further wikification is encouraged

The theory that the mental can be reduced (see reduction) to the physical is usually called physicalism. It is also called materialism or identity materialism. The term "physicalism" is less misleading because it does not have any misleading connotations; if we called the view "materialism," you might think that we were talking about something that had to do with the desire for wealth, possessions, and so forth, but obviously we're not talking about that. We're talking about a theory about the mind. "Physicalism" is better also because it implies that the mental can be reduced to whatever is physical, meaning, whatever is described ultimately by physics; and as we all know, physics describes a lot more than just matter, it also describes energy. So the view is that we can reduce mental events to events that are made up entirely of matter and energy. And remember what we mean by "reduce" here: "If I reduce X to Y, then whenever I talk about X, I can be understood to be talking about Y instead." So here's the claim: Whenever we talk about mental events, we can be properly understood to be talking about events that are made up entirely of matter and energy.

I suppose that this sounds very strange. I know it sounded very strange the first time I heard it. So let me give you an example, and I'll try to make this as plausible as I can. In fact there is a hackneyed example that is used when philosophers talk about this stuff. For some reason philosophers these days always use pain as an example of a mental event; why not pleasure, I say? There is supposed to be a certain kind of nerve fiber that leads from your limbs to your brain, called C-fibers, and whenever you're in pain, the story goes, your C-fibers are firing; and whenever your C-fibers are firing, then you're in pain. I suppose we might test this claim empirically, with experiments, right? Suppose I sit you down in my lab, and I insert some probe into your spine, right next to your C-fibers; then I find some clever way to cause you pain. You say, "Ouch!" and tell me that you are in pain. I say, "Good!" and sure enough I see that your C-fibers are firing.

My apologies if I'm getting the facts all wrong. But the point is in some such way, we are supposed to be able to study which neural states, and brain states, are associated with which mental states. Now surely that would be very interesting if we were to find that, in order to be in pain, we would have to have firing C-fibers -- wouldn't it? For that matter, a neuroscientist might notice that when you engage in deep thought, the frontal lobe of your brain is extremely active. When we engage in reasoning and complex conceptualization, the neurons in a certain part of the brain are firing; that seems to indicate that there is some sort of close association between hard thought and frontal lobe activity.

So the suggestion now is that the event of feeling pain is just the same as C-fibers firing. That is why Halverson calls the theory "identity materialism"; types of mental events, like pain, are identical to types of physical events, like C-fiber firing. So, pain is reducible to C-fiber firing. This particular theory is also called "the type-type identity theory," since mental event types are matched up with physical event types. And mind you, again, not just matched up or associated with -- but actually the very same as. The pain I experience when I bash my thumb with a hammer is really nothing more than those C-fibers going off.

Now, some of you might hear this and think that I am denying that pain, or anything mental, really exists. In other words, since I'm saying now that mental events are really only physical events, you think that I'm saying there aren't any mental events. But that is not my claim. Mental events do exist; they are simply identical to physical events of a certain kind.

It so happens that there is a theory about the mind, called eliminativism, which says that the mind, mental events, and all the rest of that simply do not exist. The best-known proponent of this theory is an American, Paul Churchland. He says that this talk of mental events, thinking and such, is all just a fiction, just folks tales, which is going to be replaced with more scientific talk, when the science of the brain and the nervous system is sufficiently developed. When that time comes, the eliminativists say, we won't use this out-dated talk of feelings, thoughts, pains, etc. We'll talk about C-fibers firing, and frontal lobes being activated, and so forth. All that talk of love, hate, decisions, beliefs, and so forth, will look antiquated and silly in the same way that talk of ghosts, demons, and witches now looks antiquated and silly. I'm not even going to tell you why some philosophers buy into this theory -- it's pretty unpopular, as you might have guessed -- I'm just telling you that it exists, so I can contrast physicalism with it. Physicalism does hold that mental events exist.

Nonetheless, you still might think that physicalism is a very strange theory, that is totally contrary to common sense. So you might object, as follows. This will be the only objection to physicalism I'll state, but it's rather complex. Just remember now all those differences that we listed between mental and physical events. Mental events are not publicly observable; they are not spatially located; they do not involve physical properties such as mass and velocity; and there is seems to be an irreducibly subjective aspect to them. How on earth could anyone say that mental events are just the same as physical events? There are all these obvious differences, so you can't reduce the mental to the physical! So physicalism has to be wrong.

Here is how the physicalist would reply. Let's go over each of those alleged differences between mind and matter. The first one is: mental events are not publicly observable. The physicalist would say: well, OK, so mental events cannot be seen by other people; but neither can the sorts of physical events we're talking about. A C-fiber firing is not only buried inside your nervous system; it is also not detectable except with special instruments. So we could very well say that C-fiber firing is not publicly observable.

If you're a dualist, you're probably not going to be happy with this reply. You'll probably say that the physicalist is missing the point. The point is really that mental events aren't observable by other people at all. Other people can't jump into my mind and as it were mentally look over my shoulder while I'm feeling pain and having deep thoughts. Maybe Mr. Spock can do that but you and I can't. So, you, or a dualist, might say, what follows from that? What follows is that feeling pain can't be the same as C-fibers firing; other people can probe my nervous system and observe my C-fibers firing but they definitely aren't observing my pain, no matter how carefully they observe my C-fibers or any other part of my nervous system. It doesn't matter; my mental states can't be observed by other people at all! That's how I think the dualist would reply.

How do you suppose the physicalist counter that? Let me play the role of the physicalist. So I would reply by saying that, really, if "publicly observable" just means "observable by other people," then your mental states are publicly observable. Mental events can be observed by other people. So what exactly would I be doing, then, if I did observe your pain? Would I have to feel your pain myself? In other words, in order for me to observe your pain, would I have to have the same aches and hurts that you have? Surely not. Why would you think that? In order for me to observe your pain, it seems to me I simply have to observe the fact that you are in pain. And if, as a physicalist, I hold that pain is the same as C-fibers firing, then all I have to do is observe your C-fibers firing, and voila -- I am observing the fact that you are in pain. The dualist isn't going to be at all happy with this reply; but let's leave that debate and move on to those other supposed differences between mind and body.

The second difference is that mental events are not spatially located. So here's how the dualist will object to physicalism on that point: mental events are not spatially located, but physical events are spatially located. So mental events are obviously different from physical events.

Here's how I, the physicalist, can reply to that point. I can concede that, for example, when I make a decision, I do not see or otherwise perceive my decision as being located anywhere. I am just immediately aware of my decision, once I?ve made it. But does that mean that the event of my decision in fact isn't located anywhere? I mean, simply because I'm not aware of its location, does it follow from that, that my decision doesn't have a location at all? I don't see how that follows. Why can't we just say: a decision is a certain type of event in the brain. When this event occurs, I'm aware of making a decision. But I am not aware of where the decision itself is taking place, namely in my brain. That doesn't mean that the decision isn't taking place in my brain. Why think that?

OK, let's look at the third alleged difference between the mental and the physical. The third difference is: mental events do not involve physical properties such as mass and velocity. The physicalist would say that neural events have electro-chemical properties; but the dualist would reply that the very idea of a mental event being a physical event in the brain and nervous system is absurd, precisely because that would mean that mental events have electro-chemical properties, and other physical properties as well.

I'll bet some of you can predict how our physicalist will reply. As the physicalist, I will say: "Why is that absurd? Let me try to figure out why you think it's absurd that mental events might have physical properties. Maybe you think that since you're not aware of any electro-chemical properties of your mental events, it somehow follows that your mental events don't have any such properties. But once again, that inference just doesn't follow. It assumes that, if all your pains, decisions, and thoughts had some electro-chemical properties, then you'd be aware of those properties. But why think that? Do you have to be aware of all of the properties that your mental events have? Do you have to be aware of everything that is true of the processes of your mind? Of course not. There is a lot of unconscious stuff going on in your mind, a lot of stuff you're not aware of. So then, why not think that your decisions, your pains, and other mental events have electro-chemical properties? The only thing that would make that suggestion absurd is if you thought you had to be aware of everything going on in your mind. But you don't have to be aware of everything going in your mind.

Finally, let's look at the fourth supposed difference between the mental and the physical. It is probably the hardest to deal with: there seems to be an irreducibly subjective aspect to mental events. In other words, there is a first-person, felt, immediate, personal, subjective aspect to mental events. Physical events do not have this subjective aspect; physical events are not qualia. When dualism claims this, it is basically throwing down the gauntlet to physicalism. "Look," the dualist says, "there just is this subjective aspect to my pain; it makes sense to ask, ?What does your pain feel like?? But it doesn't make sense to ask, ?What does your C-fiber firing feel like?? C-fiber firing does not have this subjective aspect. So you can't reduce pain to C-fiber firing."

How could a physicalist reply to this? Well, I think it's not as difficult a problem as some might like to make it out to be. If I'm a physicalist, then my claim is that C-fiber firing, or maybe some other brain event, just is awareness of pain. And so it follows, of course, that C-fiber firing, or the brain event, does have a subjective aspect; and that it does make sense to ask, "What does your C-fiber firing feel like?"

But once again, the dualist is likely to say, "OK, say we open you up and look at your C-fibers firing away. Are we going to see this subjective aspect, the pain qualia that we talked about?" Well, the answer to that is clearly no. But is that a problem? After all, we experience pain only if it's our C-fibers that are firing. If you open my spine up and use scientific instruments to look at my wildly firing C-fibers, then of course you won't be experiencing pain. In order for you to experience pain, your C-fibers would have to be firing. So here's the point then: the dualist wants to object that a physical event cannot have a subjective aspect; the physicalist protests and says there's no good reason not to think that physical events can have subjective aspects. Why couldn't they? We can detect a physical event in someone else without ourselves being in a subjective state. But so what? Why should I expect to be in pain when I see someone else's C-fibers fire? It's only the firing of my own C-fibers that constitutes my own pain. So, President Clinton to the contrary notwithstanding, he cannot feel my pain!

So on all four counts, the physicalist has a way to explain how these supposed differences between the mental and the physical aren't really differences at all. This undermines crucial support for dualism and greatly increases the plausibility of physicalism. It is not so absurd, or at least not so obviously absurd, to say that types of mental events are the same as, and reducible to, some types of physical events. We just have to put these issues in the right light. And physicalism has one very clear advantage over dualistic interactionism, namely, that there is no mystery about how the interaction between mental and physical events takes place. Right? Simply because mental events are, at bottom, themselves types of physical events.

I have given you some ways that the physicalist could reply to the dualist's objections; in so doing, I tried to make it plain how some people can hold what, on first glance at least, looks like an absurd claim, that mental events are simply a type of physical event -- brain or neural events. Now I should note that this is just one kind of physicalism; we may call it neural type physicalism, because it says that mental event types are types of nervous system events. It is more commonly called "the type-type identity theory."

I'm going to present an objection to neural type physicalism. But first I'm going to present another kind of physicalism; I'm going to discuss it very quickly, because mainly I want to use it to make quite clear how neural type physicalism is only one kind of physicalism. In the middle of this century, it was very fashionable to try to reduce mental events to behavior. This view is called analytical behaviorism, because the idea is that we can ultimately analyze, or reduce, talk of mental events and processes in terms of things that humans say, express, and do. In other words, analytical behaviorism says that what a mental event is, is a propensity, a tendency, to display a certain set of behaviors -- words, facial expressions, bodily postures, and actions. If you want to see whether someone believes that God exists, you look at what he says, how he reacts when you say "God exists," whether he goes to church, and so on. And his belief is constituted by those behaviors; in other words, there isn't any more to his belief that God exists than those behaviors. Or to take another example, the good old example of pain. Analytical behaviorism would say that pain is nothing more than the tendency to wince, to grimace, to pull back quickly from the source of something causing bodily damage, to say "ouch" and "that hurts," and similar behaviors. That's all there is to pain!

Well, I'm not going to discuss the merits of analytical behaviorism. Hardly anyone believes it anymore. Good riddance, I say. But this theory is an example of another kind of physicalism. Why? Because it does say that mental events are reducible to physical events; behaviors are physical events, and behaviorism says that mental events are reducible to behaviors. So how does behaviorism different from the sort of physicalism I was talking about last time, neural type physicalism? Well, it's a different type of physical event that mental events are being reduced to. On the one hand, neural type physicalism says that mental events can be reduced to types of neural or brain events. On the other hand, analytical behaviorism says that mental events can be reduced to types of behavioral events. So basically here's a question we might ask: If types of mental event can be reduced to types of physical event, then which types of physical event? Neural type physicalism gives one answer; analytical behaviorism gives a different answer.

This leads me, finally, to that objection to neural type physicalism that I said I was going to give. The objection is this: we have construed the types too narrowly. Maybe there are types of physical events that mental events might be reducible to, that are nothing like neural states. I'd better give you an example if you're to see what I'm talking about. Suppose after some years, superscientists were to build a robot that was given sensory receptors, could talk intelligently on a wide variety of subjects, could carry out a variety of difficult tasks, and even had what appeared to be emotional reactions to its surroundings -- and so forth. In short, somehow, scientists had created what appeared to be a conscious, intelligent machine. Now, there is considerable debate over whether such a machine is possible -- whether it is possible to, as it were, build a mind from scratch. But just assume, for the sake of argument, that such a machine is possible, and that it does have thoughts, perceptions, feelings, and so on. So then mental events are occurring in this machine.

Now let's say our superscientists did not use anything much like the human nervous system to build this robot. They used some sort of special circuitry -- very high-tech microchips and whatnot. In that case, it is not any type of neural or brain event to which we would reduce the robot's mental events. It would be a -- what should we call it? -- a circuitry event! And then in that case mental events could be reducible not just to neural events, but also to circuitry events. So here then is the objection to neural type physicalism: the types we're reducing mental events to is too narrow. To include the mental events of high-tech conscious robots, we should describe the physical events in some way that would include both neural events and circuitry events. Not just neural events.

Or suppose that there is intelligent life elsewhere in the universe. So there might be some alien species that does not have anything quite like our brain or nervous system. Say this species is intelligent, and conscious, and has a mind, but its mental events are identical to a different type of physical event; instead of neurons, they have schmeurons, say. Well then, if we want to be physicalists, then we should allow that mental events can be reduced to neural events, or circuitry events, or to schmeural events! As you can see, the list might go on.

In any case, I think that this neatly refutes neural type physicalism. Neural type physicalists are biased in favor of the physical types that the human species has. So philosophers of mind, trying to be clever, have named this bias species chauvinism. That means that neural type physicalists are irrationally disposed in favor of their own species, when it comes to describing the physical types that mental events reduce to, or are identical to.

Suppose after all this, I still think that dualism is wrong, and I admit that neural type physicalism is wrong; but I still think that some kind of physicalism is still basically right. I think that everything basically has to reduce to the physical; only the physical exists ultimately. So then what are my options? Is there a way for me to hold onto physicalism, so I can get around the species chauvinism accusation? Well, there are basically two ways. The first way is find an even broader type of event, which describes all the different specific physical event types that different species, or robots, might have. This is called functionalism. The second way is to deny that we are reducing mental event types, and talk instead of reducing mental event tokens. This I will call token physicalism. I'm not going to talk about either theory in much depth, because I'll tell the truth -- by now we have gotten quite far away from any issues that were talked about throughout most of the history of philosophy. All of these issues about the different kinds of physicalism have arisen in the last fifty or sixty years or so.

So first I will briefly explain functionalism. Functionalism asks: what do neural events, and circuitry events, and schmeural events all have in common? The answer: it can't be any particular type of physical hardware that they have in common. It's not neurons, microchips, or schmeurons. So what do they have in common? What they have in common is that they are all structurally similar, or functionally similar. What do I mean by that? Well, to similar sorts of inputs, each of these physical types gives a similar sort of output. Let me give a simple example. The human, the robot, and the alien are all going to feel pain when you damage their bodies; and they are all going to have roughly similar reactions, such as announcing that they're in pain, avoiding the source of the damage, and perhaps striking back or getting angry.

So here is a simple definition of "functionalism":

Functionalism is the view that mental events are the same as functional states; and a functional state is a state a physical system is in, when it has a set of sensory and other inputs, together with a set of potential behavioral outputs.

So say I'm thinking about bananas. That mental event is, according to functionalism, a functional state; and that just means a state described by various inputs and outputs. For example, an input would be that someone has said the word "bananas" to me and off I go thinking about bananas; and then a potential output would be to go get a banana and eat it. So my mental event, thinking about bananas, is just a functional state, and the functional state is specified by the inputs of the event and the outputs of the event.

Well of course there is a lot we could say about functionalism. For one thing, if all we have at our disposal, to describe mental events, is their inputs and outputs, then have we really described the mental event itself adequately? It would be a little like saying that an oak tree could be adequately described like this: "Oak trees result from acorns (that's the oak tree input) and they are cut up to make tables (that's the oak tree output)." Yeah, but (you might ask) what is an oak tree itself? You might ask a similar thing of functionalists. "OK, so mental events have certain inputs and outputs; I can accept that; but what is a mental event itself?" Unfortunately, we don't have time to go into it. But for what it is worth, functionalism is probably the most popular theory of mind today. So obviously a lot more can be said about it.

I said there is a second way to get around the species chauvinism objection. This can be called token physicalism. More commonly called "the token-token identity theory." Whatever you want to call it, I'll define as follows:

Token physicalism is the view that tokens of mental events may be reduced to tokens of physical events.

The idea here is that we are giving up trying to give general accounts of mental event types. So for example we won't try to reduce the whole category of pleasure, or the whole category of pain, to any single mental event type. We'll focus in on individual, single, pleasures and pains. And we say, of those mental event tokens, that each one is identical to, and reducible to, some physical event token. In our case, we might say that an individual pain is the same as an individual instance of my C-fibers firing. But we might say something quite different about the pain of an alien from Alpha Centauri. The point in either case, though, is that it's tokens of mental events that are reduced to tokens of physical events.

I'm just going to give one little objection to this theory. Namely, what does the following phrase mean? -- "Token of a mental event." Token physicalism can't tell us. I mean, suppose a scientist had reduced a slew of mental event tokens to physical event tokens. So I'd say, "Great work! But just what do all of those mental event tokens have in common, that makes us say that they are tokens of mental events, as opposed to any other kind of event?" What distinguishes the mental event tokens from tokens of other kinds of events? That's the question: What distinguishes mental event tokens? Dualism, remember, says that the mental is an ultimate, fundamental category of being; it can't be explained in terms of anything nonmental. So dualism doesn't have to answer this question. And neural type physicalism at least promises to answer the question; it says that we will discover just exactly what all the different mental events have in common, which makes them all mental events; and it's going to be some special type of event in the brain.

But token physicalism can't answer this question; it can't tell us what mental event tokens have in common; and why not? Because if any theory tells us what mental event tokens have in common, then the theory is describing mental event types. Just think: that is precisely what mental event tokens have in common: they are all tokens of mental event types. What do human pain and alien pain in common? They are both tokens of the type, pain. So, if we describe what all mental event tokens have in common, then we have for that very reason described a mental event type! And then the token physicalist would have to talk about mental event types; and that means we?ve basically given up token physicalism. Well, that's the only thing I'm going to say about token physicalism. My usual disclaimers apply.

In the interests of mercy, let me say that I'm not trying to make you believe that we can't know which theory of mind is correct -- I don't want you to leave class being skeptics about philosophical questions about the mind. Generally, in the interests of objectivity and general intellectual responsibility, I feel it is my duty to tell you about most of the leading philosophical theories of the different subjects we're studying, and some arguments for and against them. So, the mere fact that I'm not telling you that one theory is The Truth doesn't mean that I have no views about what The Truth is. In fact, I do think that one particular theory of mind is better than the others -- I'm just not telling what it is! And the mere fact that I'm presenting objections to all of the theories I?ve stated doesn't mean that I think we can't know which one is correct, or that they are all false; all I'm trying to do is to introduce you to the issues. Philosophical issues are more complicated than you might have thought when you came into this class. So if you want to have really well-informed views on these issues, it's just the same as having really well-informed views on issues in chemistry, or in political science, or in computer programming. It's going to take research and long hard thinking.

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Physicalism."

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Physics

(From Wikipedia, the free Encyclopedia)

Physics (from Greek from φυσικός (phusikos): natural, from φύσις (fysis): Nature) is the science of Nature in the broadest sense. Physicists study the behaviour and interactions of matter and radiation. Theories of physics are generally expressed as mathematical relations. Well-established theories are often referred to as physical laws or laws of physics; however, like all scientific theories, they are ultimately provisional.

Physics is very closely related to the other natural sciences, particularly chemistry, the science of molecules and the chemical compounds that they form in bulk. Chemistry draws on many fields of physics, particularly quantum mechanics, thermodynamics and electromagnetism. However, chemical phenomena are sufficiently varied and complex that chemistry is usually regarded as a separate discipline.

Below is an overview of the major subfields and concepts in physics, followed by a brief outline of the history of physics and its subfields. A more comprehensive list of physics topics is also available.

Overview of physics

Theories

Main article: Theories of Physics

Central theories

Classical mechanics -- Thermodynamics -- Statistical mechanics -- Electromagnetism -- Special relativity -- General relativity -- Quantum mechanics -- Quantum field theory -- Standard Model -- Fluid mechanics

Proposed theories

Theory of everything -- Grand unification theory -- M-theory -- Loop quantum gravity -- Emergence

Fringe theories

Cold fusion -- Dynamic theory of gravity -- Luminiferous aether -- Orgone energy -- Reciprocal System of Theory -- Steady state theory

Concepts

Matter -- Antimatter -- Elementary particle -- Boson -- Fermion

Symmetry -- Motion -- Conservation law -- Mass -- Energy -- Momentum -- Angular momentum -- Spin

Time -- Space -- Dimension -- Spacetime -- Length -- Velocity -- Force -- Torque

Wave -- Wavefunction -- Quantum entanglement -- Harmonic oscillator -- Magnetism -- Electricity -- Electromagnetic radiation -- Temperature -- Entropy -- Physical information

Phase transitions -- Critical phenomena -- Spontaneous symmetry breaking -- Superconductivity -- Superfluidity -- Quantum phase transitions

Fundamental forces

Gravitational -- Electromagnetic -- Weak -- Strong

Particles

Main article: Particless

Atom -- Proton -- Neutron -- Electron -- Quark -- Photon -- Gluon -- W boson -- Z boson -- Graviton -- Neutrino -- Particle radiation--Phonon--Roton

Subfields of physics

Astrophysics -- Atomic, Molecular, and Optical physics -- Computational physics -- Condensed matter physics -- Cosmology -- Cryogenics -- Fluid dynamics -- Polymer physics -- Optics -- Materials physics -- Nuclear physics -- Plasma physics -- Particle physics (or High Energy Physics) -- Vehicle dynamics

Methods

Scientific method -- Physical quantity -- Measurement -- Measuring instruments -- Dimensional analysis -- Statistics

Tables

List of physical laws -- Physical constants -- SI base units -- SI derived units -- SI prefixes -- Unit conversions

History

History of Physics -- Famous Physicists -- Nobel Prize in physics

Related Fields

Astronomy and Astrophysics -- Biophysics -- Electronics -- Engineering -- Geophysics -- Materials science -- Mathematical physics -- Medical physics -- Physical Chemistry

A brief history of physics

Note: The following is a cursory overview of the development of physics. For a more detailed history, please refer to the main article on this subject, History of physics.

Since antiquity, people have tried to understand the behavior of matter: why unsupported objects drop to the ground, why different materials have different properties, and so forth. Also a mystery was the character of the universe, such as the form of the Earth and the behavior of celestial objects such as the Sun and the Moon. Several theories were proposed, most of them were wrong. These theories were largely couched in philosophical terms, and never verified by systematic experimental testing. There were exceptions and there are anachronisms: for example, the Greek thinker Archimedes derived many correct quantitative descriptions of mechanics and hydrostatics.

During the late 16th century, Galileo pioneered the use of experiment to validate physical theories, which is the key idea in the scientific method. Galileo formulated and successfully tested several results in dynamics, in particular the Law of Inertia. In 1687, Newton published the Principia Mathematica, detailing two comprehensive and successful physical theories: Newton's laws of motion, from which arise classical mechanics; and Newton's Law of Gravitation, which describes the fundamental force of gravity. Both theories agreed well with experiment. Classical mechanics would be exhaustively extended by Lagrange, Hamilton, and others, who produced new formulations, principles, and results. The Law of Gravitation initiated the field of astrophysics, which describes astronomical phenomena using physical theories.

From the 18th century onwards, thermodynamics was developed by Boyle, Young, and many others. In 1733, Bernoulli used statistical arguments with classical mechanics to derive thermodynamic results, initiating the field of statistical mechanics. In 1798, Thompson demonstrated the conversion of mechanical work into heat, and in 1847 Joule stated the law of conservation of energy, in the form of heat as well as mechanical energy.

The behavior of electricity and magnetism was studied by Faraday, Ohm, and others. In 1855, Maxwell unified the two phenomena into a single theory of electromagnetism, described by Maxwell's equations. A prediction of this theory was that light is an electromagnetic wave.

In 1895, Roentgen discovered X-rays, which turned out to be high-frequency electromagnetic radiation. Radioactivity was discovered in 1896 by Henri Becquerel, and further studied by Pierre Curie and Marie Curie and others. This initiated the field of nuclear physics.

In 1897, Thomson discovered the electron, the elementary particle which carries electrical current in circuits. In 1904, he proposed the first model of the atom, known as the plum pudding model. (The existence of the atom had been proposed in 1808 by Dalton.)

In 1905, Einstein formulated the theory of special relativity, unifying space and time into a single entity, spacetime. Relativity prescribes a different transformation between reference frames than classical mechanics; this necessitated the development of relativistic mechanics as a replacement for classical mechanics. In the regime of low (relative) velocities, the two theories agree. In 1915, Einstein extended special relativity to explain gravity with the general theory of relativity, which replaces Newton's law of gravitation. In the regime of low masses and energies, the two theories agree.

In 1911, Rutherford deduced from scattering experiments the existence of a compact atomic nucleus, with positively charged constituents dubbed protons. Neutrons, the neutral nuclear constituents, were discovered in 1932 by Chadwick.

Beginning in 1900, Planck, Einstein, Bohr, and others developed quantum theories to explain various anomalous experimental results by introducing discrete energy levels. In 1925, Heisenberg and 1926, Schrödinger and Dirac formulated quantum mechanics, which explained the preceding quantum theories. In quantum mechanics, the outcomes of physical measurements are inherently probabilistic; the theory describes the calculation of these probabilities. It successfully describes the behavior of matter at small distance scales.

Quantum mechanics also provided the theoretical tools for condensed matter physics, which studies the physical behavior of solids and liquids, including phenomena such as crystal structures, semiconductivity, and superconductivity. The pioneers of condensed matter physics include Bloch, who created a quantum mechanical description of the behavior of electrons in crystal structures in 1928.

During World War II, research was conducted by each side into nuclear physics, for the purpose of creating a nuclear bomb. The German effort, led by Heisenberg, did not succeed, but the Allied Manhattan Project reached its goal. In America, a team led by Fermi achieved the first man-made nuclear chain reaction in 1942, and in 1945 the world's first nuclear explosive was detonated at Trinity site, near Alamogordo, New Mexico.

Quantum field theory was formulated in order to extend quantum mechanics to be consistent with special relativity. It achieved its modern form in the late 1940s with work by Feynman, Schwinger, Tomonaga, and Dyson. They formulated the theory of quantum electrodynamics, which describes the electromagnetic interaction.

Quantum field theory provided the framework for modern particle physics, which studies fundamental forces and elementary particles. In 1954, Yang and Mills developed a class of gauge theories, which provided the framework for the Standard Model. The Standard Model, which was completed in the 1970s, successfully describes almost all elementary particles observed to date.

Future directions

As of 2003, research is progressing on a large number of fields of physics.

In condensed matter physics, the biggest unsolved theoretical problem is the explanation for high-temperature superconductivity. Strong efforts, largely experimental, are being put into making workable spintronics and quantum computers.

In particle physics, the first pieces of experimental evidence for physics beyond the Standard Model have begun to appear. Foremost amongst this are indications that neutrinos have non-zero mass. These experimental results appear to have solved the long-standing solar neutrino problem in solar physics. The physics of massive neutrinos is currently an area of active theoretical and experimental research. In the next several years, particle accelerators will begin probing energy scales in the TeV range, in which experimentalists are hoping to find evidence for the higgs boson and supersymmetric particles.

Theoretical attempts to unify quantum mechanics and general relativity into a single theory of quantum gravity, a program ongoing for over half a century, has yet to bear fruit. The current leading candidates are M-theory and loop quantum gravity.

Many astronomical phenomena have yet to be explained, including the existence of ultra-high energy cosmic rays and the anomalous rotation rates of galaxies. Theories that have been proposed to resolve these problems include doubly-special relativity, modified Newtonian dynamics, and the existence of dark matter. In addition, the cosmological predictions of the last several decades have been contradicted by recent evidence that the expansion of the universe is accelerating.

See unsolved problems in physics for a fuller treatment of this subject.

Suggested reading and external links

• Physics book and study guide on Wikibooks site.
• Feynman, The Character of Physical Law, Random House (Modern Library), 1994, hardcover, 192 pages, ISBN 0679601279
• Feynman, Leighton, Sands, The Feynman Lectures on Physics, Addison-Wesley 1970, 3 volumes, paperback, ISBN 0201021153, hardcover Commemorative edition, 1989, ISBN 0201500647
• Brian Greene, The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory, 464 pages, paperback, Vintage Books, 2000, ISBN 0375708111, hardcover, W.W. Norton & Company, 2003, ISBN 0393058581
• Eric Weisstein, Weisstein and Wolfram Research, Inc., and et al, World of Physics. Online Physics encyclopedic dictionary.
• Carl R. Nave, HyperPhysics, . Online crosslinked physics concept maps.

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Physics."

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Touch

(From Wikipedia, the free Encyclopedia)

Touching is having or getting a zero distance; in geometry it refers especially to a tangent line or curve. See also collision.

Touch may simply be considered one of five human senses. However, when a person touches something or somebody this gives rise to various feelings: the perception of pressure (hence shape, softness, texture, vibration, etc.), heat, cold and sometimes pain. Thus the term "touch" is actually the combined term for several senses, see sense. Holding or moving something is usually done by touching (exceptions are e.g. blowing or using a magnet or engine), but this is sometimes done indirectly, e.g. with pliers.

Touching another person is a form of physical intimacy and plays an important role in human sexual behavior, but also in physical abuse, such as striking, pushing, pulling, pinching, kicking, etc.

Touching is a form of nonverbal communication [1].

Human babies have been observed to have enormous difficulty surviving if they do not possess a sense of touch, even if they retain sight and hearing. Babies who can feel the sense of touch, even without sight and hearing, fare much better. The implications are intriguing from an AI perspective. Touch can be considered a basic sense in that nearly all life forms have a response to being touched, while only a subset have sight and hearing.

See also frotteurism, grappling, massage, tickling.

Quote (Leonard Cohen): I needed so much/ To have nothing to touch/ I've always been greedy that way.. -from The Night Comes On (1984)

One can also be emotionally touched. In this sense it refers to some action or object that has evoked a sad or joyful emotion.

For example to say "I was touched by your letter" would not imply you were angered by it, but that you felt joy or sadness when reading it.

"Touch" is one of the most traditional Manga in Japan. It is about brothers who play baseball, trying to play at the Koushien. The youger brother is called the Katsuya, and the older brother is called Tastuya, and they were twins. In fact, Tastuya had never played baseball until he entered the high school. Comparing to this, Kastuya was a very fomous baseball player since he was in middle school, but he died when he was in the first grade in high school by a car accident. Kastuya's death made Tastuya play baseball to accomplish Kastuya's dream. When Kastuya was alive, these two boys fell in love with a same girl, called Minami, who was a childhood friend with Tastuya and Kastuya. After Kastuya's death, Tastuya and Minami supported eachother to accomplish eachother's goal. Tastuya's goal was to play baseball at the KOUSIENN, and Minami's goal was to do a good performance at the All Japan Gymnastic Tournament. They fell in love gradually but Tastuya can't show his emotions that he loves Minami because of his dead brother. He knew that Kastuya loved Minami too, so he feels a sense of guilt to Kastuya. This Manga creates a story of their difficult love and their enshusiasm towards their sports.

A 102-episode anime TV series, three movies, and one TV special were also produced.

Touch is a rock band.

Touch is also a record label concentrating on experimental electronic music - see Touch (record label). Touch is a novel by Elmore Leonard, later made into a film directed by Paul Schrader and starring LL Cool J, Christopher Walken, and Skeet Ulrich. touch is a program on Unix and Unix-like systems used for changing the date and timestamp on a file, but is also often used for creating an empty file. The command-syntax is:

touch [options] 

If that file exists, its current details are updated as if a user edited the file and saved it again, but if the file does not exist, a file with the name specified in the current directory will be created with a timestamp corresponding to the present time of the system clock. touch can also be invoked with a plethora of options to change the files timestamp to something other than the current date and time. The version of touch bundled in coreutils that is distributed by the FSF and found on most GNU/Linux systems was written by Paul Rubin, Arnold Robbins, Jim Kingdon, David MacKenzie and Randy Smith.

Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Touch."

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Abbreviations & Acronyms: Physical

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Synonyms within Context: Physical

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Modern Usage: Physical

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Commercial Usage: Physical

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Image Slideshow: Physical

Photos: Physical More pictures...

Illustrations: Physical More pictures...

Computer Images: Physical More pictures...

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Photo Album: Physical

Thumbnail	Description & Credit	Thumbnail	Description & Credit
	Members of the first National Advisory Cancer Council at the groundbreaking ceremonies at the NCI's building 6 in June, 1938. (Left to right) Francis Wood, C.C Little, James Ewing, Arthur Compton, James Conant, Thomas Parran, and Ludwig Hektoen. This new building, erected on land donated by Mrs. Luke J. Wilson was the fourth to be constructed in the complex that is now the National Institutes of Health. The structure was unique in that year of 1939, with its physical equipment and facilities designed solely for scientific research in a specialized field of science. Building 6 was to house the National Cancer Institute, the first of the nine specialized institutes that would comprise NIH. See also ar003810. Credit: Unknown photographer/artist.		This illustration with and without text, titled "How Cancer Spreads" explains the process of metastasis. Once metastatic cells are attached to the basement membrane (a physical barrier that seperates tissue components), they break through with the help of an enzyme called type IV collagenase. Cancer cells then move through the blood stream enabling them to spread to other parts of the body. A secondary tumor may form at another site in the body. See artwork: GA-17. Credit: Jane Hurd (artist).
	A pregnant woman with syphilis can pass T. pallidum to her unborn child, who may be born with serious mental and physical problems as a result of this infection. When a newborn is affected it is known as “Congenital Syphilis”. Credit: CDC.		Biological safety cabinets and other physical containment devices should be used, whenever conducting procedures that have a high probability for generating aerosols. These labs were also referred to as the “Box Labs”. Credit: CDC.
	Vice Admiral H. Arnold Karo Expedition leader on OCEANOGRAPHER round the world cruise Karo was responsible for building the NOAA fleet of the 60's through early 90's Karo's vision was the multi-disciplinary ship OCEANOGRAPHER used for physical, geophysical, and meteorological oceanography. Credit: Coast & Geodetic Survey Historical Image Collection.		Henry Mitchell Assistant in the Coast and Geodetic Survey Accomplished hydrographer and physical oceanographer Pioneered many techniques used in studying circulation of estuarine environments. Credit: Coast & Geodetic Survey Historical Image Collection.
	Flat Creek at Keswick Reservoir near Redding, CA. The creek needs additional physical restoration except for copper from Stowell Mine the creek is chemically clean. Credit: NOAA Restoration Center.		The first in a series of images showing NOAA scientists at the 1997 transplant site just before transplanting the eelgrass turf. Scientists worked in dry suits in the cold Bay waters and used surface air supplies at the mostly shallow sites. Zostera marina requires a specific set of physical conditions to thrive. The plants need light, nutrients and protection from excessive wave energy. Credit: NOAA Restoration Center.
	Figure 4. Scoresby insulated bottle invented by William Scoresby, an early Nineteenth Century whaler with a passion for studying the physical sciences. His first model of this water sampling bottle was invented about 1809. Left: descending. Right: ascending. Credit: Sailing for Science - the NOAA Fleet Then and Now.		Figure 67. The bathythermograph first conceived by Athelstan Spilhaus in 1936 and produced in 1937. This instrument measured a continuous profile of sea- temperature versus depth. It was the prototype of many types of instruments used either for studies of physical oceanography or for use by the undersea warfare community. Credit: Sailing for Science - the NOAA Fleet Then and Now.
Source: pictures compiled by the editor from various references; see picture credits.

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Digital Photo Gallery: Physical
 

"Dark Face" by Elisabeth Howe Commentary: "My face (this photo hasn't been modified at all, so I don't know what that says about my physical appearance? hm)."	"Expression 1" by Jillian Balfour Commentary: "Expression: a facial aspect / look or physical position that conveys a special feeling. (my lovely aunt and niece, walking at the zoo. the trust of a child is a sweet thing.)."
Source: photographs selected by