Cause Definition and 572 Threads

i wish to know why have plants with exactly required medicinal value has evolved. is there a some sort of lock and key like reason which helps to evolve medicinal plants for many disease? i also want to the logic behind using water and other solvent for extraction of solvents. some time...

If the tensor tympany is loose, the ear drum is also loose. But then, the ear drum will vibrate even by weak sound waves, which will cause increased vibration of malleus, incus, and stapes. Isn't that supposed to cause hyperacusis instead?

Let A be the set of possible states of the world, or possible preferences a person could have. Let G(A) be the set of "gambles" or "lotteries", i.e. the set of probability distributions over A. Then each person would have a preferred ordering of the states in A, as well as a preferred ordering...

So I look at the Minowski diagrams, and I can understand that moving on the y means moving in time, and moving on the x means moving in space, but drawing some diagrams of my own, I find it impossible to see why it would imply FTL travel. All objects travel either directly on the x...

During fight-or-flight situations, alpha 2 receptors ( which are inhibitory receptors ) of the pancreatic beta cells are stimulated, and as a result there's decreased insulin production. While it benefits the body by producing increased blood sugar level, I don't understand why Insulin doesn't...

I've been having a problem lately with my computer. It's running 64-bit Windows 7, and has two external hard drives plugged in. Occasionally , I've noticed that sometimes when I attempt to do something in a program, even something as single as right-click on a cell in Excel, the computer will...

http://en.wikipedia.org/wiki/Turner_Syndrome As in being X0 rather than XX or XY I thought that the X you get from your mother and the X you get from your father all coded for the same things. I wouldn't have imagined anything would happen rather than all of the recessive genes on the X...

Homework Statement Imagine a cyclist (in spacesuit) cycling on the level on the Moon (so no drag). The external forces acting on them are contact force upwards (from Moon) and weight downwards (from Moon), which balance. Plus an unbalanced friction force forwards (from Moon on the tyres). I...

The de broglie bohm theory posits that the photon goes through one of the slits and the waves through both. (In a single particle double slit experiment) The waves are probability waves, however they must be modelling an underlying resource. Thus would they create some sort of unequalness...

i have a cheap polarizing shade i bought from walmart. i aligned my polarizing shades with the polarized light coming from my laptop, however not all the light was blocked. just to be extra sure that it wasn't my lcd that was being weird, i rotated a laser beam through my polarizing shades, and...

http://www.russianspaceweb.com/proton_glonass49.html#culprit Seems like a simple mechanical interlock (notch or flat) could have prevented this problem. http://xkcd.com/1133/

I started general last year and I was wondering why space/time does not cause fricton. Since it has such an effect on large bodies such as our solar system that occupy space in it and with the cassamir effect we know a vacuum can interact with matter under the right conditions. It just seems...

Homework Statement Describe the forces acting on the shaft AB Homework Equations The Attempt at a Solution I've ignored the bearings for now... but I know each of them has 2 forces, 1 in the radial direction and the other in the tangential direction ... Anyway, this is my diagram (sans...

Why do frequent water changes cause aquatic plants to grow faster? In an aquarium, the more frequent the water changes the faster flora grow. But why is that?

Need some help here! My plant just installed a water scrubber for controlling methanol emissions. Results obtained from stack tests have consistently shown the flow rate of the gasses from the scrubber outlet is about 30% of gas flow rate into the scrubber. From process knowledge, most of the...

In the double slit experiment wavicles go through one slit of the other in roughly a 50/50 ratio. How does this not violate conservation of momentum? They would need momentum to push them to the right or the left.

Hi guys, I know this is a simple question. But when an artery is blocked it is easier to understand because, less oxygen goes to tissue so, necrosis of tissue. But when a vein is blocked, only the draining is affected, the arteries are still able to supply oxygen, but why does necrosis still...

Am I wrong in thinking that the rf radiation used in nmr is not "absorbed" by protons to cause transitions between spin states but rather it is only there to provide a magnetic field which can rotate the magnetisation vector away from the primary field?

For our physics lab we found the magnetic field produced by a magnet at different distances. When graphing the data, it was supposed to produce a linear graph when we plot the field strength against 1/r3. However, my graph doesn't become linear until 1/r5 (however, it does linearize quite nicely...

I read somewhere that a magnetic field is caused by the spin of a charge particle, in most cases the electron. So, I take it then that the electrons in the eddy currents in a bar magnet are all spinning in the same direction? Also, do those eddy currents induce currents in the virtual electrons...

Force is naturally associated with something acting on anything. Eletromagnetic forces are bipolares, i.e., charges are of opposite signals to atract one another. Why gravity is monopolar ? The einsteins elastic rubber example imply on a kind of hyerarchy of forces, so, it would possible that...

If I'm correct, Cherenkov radiation is caused when particle moves faster than light in a certain medium. Can neutrinos, say, traveling through water, cause Cherenkov radiation then? Or is there a property of neutrinos which prevents that?

Homework Statement Two people start running from rest. The first person has a mass of 59 kg and is wearing dress shoes with a coefficient of static friction of 0.52. The other person is wearing running shoes with a coefficient of static friction of 0.66. Explain why we do not really need...

Hi, I'm a bit confused by induced drag on an aerofoil and hoping somebody can clear it up for me. I understand that as air slips around the edges of the wing due to the pressure differential between the top and the bottom surfaces, the angle of attack at the ends of the wings is...

many transition elements have variable oxidation state like Fe.what is the exact cause for this?they may not obey the octet rule,but what is the reason behind this?Also,elements like nitrogen are not transition elements and still show variable valency.what will be the electronic configuration of...

I was just wondering if a person wearing convex lenses looks at a light source... Will excess heat be generated in his eyes? As it is a converging lens.. Thanks!

A tiny pellet thrown by hand would never harm a glass window , but fire that pellet from a shotgun and it will shatter the glass into pieces , obviously the speed of the pellet made all the difference here .. how could this be explained on the actual atomic level (I understand the theoretical...

I was recently told virtual particles don't cause decoherence. Why not? Do they just never interact with their environment (apart from transferring energy/force) so they can never collapse a wavefunction?

I have a question about precession. I have seen a few videos on youtube. A bicycle wheel that is attached to a thread on one side. The wheel is aligned upright, and spun by hand. The "experimentist" release the wheel, and precession starts right away due to the vertical torque applied by...

I just bought a rather "cheap" lamp from Target and when I unpack it I find a sheet of paper with the warning "this product is known to the state of california to cause cancer". Well isn't that great. thanks a lot! There is a little tag on the electrical cord that says I should wash my hands...

ok thank you << Moderator's Note -- Do NOT delete your posts after you have received help. That is cheating, and it will not be tolerated here. You agreed to the PF rules when you joined here, and the rules are ver explicit about not altering your posts after you have received help. You...

Hello, This is a multi-part question that stems from understanding how X-ray diffraction occurs in crystals (eg. protein crystals). 1. Diffraction occurs when Bragg's Law is satisfied, but I'm sure the waves aren't actually being reflected. The x-ray's are scattering. What type of...

I understand a little about eddy currents and synchrotron radiation; I believe I am correct in saying that they are examples of energy loss (essentially drag) when moving though a gradient of magnetic flux. But are there any materials/effects/things that cause drag when moving through a uniform...

please explain it...

As i have learnt, the lenz's law is not the cause of the meissner effect.This can also be proved by some experiments.I was wondering what may be the real cause for the meissner effect? As i don't know the cause, i have no idea, in which part of physics i must post this query.

Hello, I was interested in human consciousness, and I picked up Daniel Dennett's book "Consciousness Explained" and something he claims there got me thinking: He says that human brain evolved from chimp-size to homo-sapiens-size in a period after humans learned to stand on 2 feet, and before...

What causes sound to be effected by the thickness and length of its vibrating object? Is it that the length that the sound travels along giving more rotational room? assuming it is like a string plucked? Does sound have a standard "length" that is compressed or stretched dependent on the...

Before I say anything, I don't really have any experience in physics. But this question just popped into my mind concerning cause and effect and I can't seem to find the answer to it on the web. Here it is...Are cause and effect the same thing if a frame of reference is not present? For...

I read about long term use of these kinda antidepressants causing hippocampal neurogenesis and stuff like that but I'm focusing more on what long term use does to the various monoamine neurotransmitter pathways. I'll start with SSRIs because they are the simplest. Their main mechanism of action...

Could a universal "Oort cloud" structure cause expansive acceleration? Could there be a giant sphere of invisible non-reactive matter (neutrinos?), left over from the big bang, so massive that it's gravity is pulling galaxies outward? I know the Oort cloud doesn't pull planets outward, but...

Not sure if this is in the right section, but anyway... Homework Statement Explain the primary cause of the force experienced by the rod. In your explanation you must refer to the magnetic field generated by the current. The rod is carrying current perpendicular to the magnetic field...

From what I've gathered, compounds such as amphetamine, ephedrine and tyramine are taken into noradrenergic (and dopaminergic) cells via the uptake transporters, then when in the cytosol they get taken into the synaptic vesicles via the vesicular monoamine uptake transporter. Like that, they...

What is today the most accepted postulate about the cause of Earth's rotation? Faradey's motor or the elements that initially made Earth were rotating around a center of mass, and the velocity remained, or something else? English is not my mother language, sorry if I wrote something wrong.

Homework Statement In the context of image reconstruction using backprojection by CT scanners - Why / how does backprojection cause star blur? Homework Equations Figure 13 of http://depts.washington.edu/nucmed/IRL/pet_intro/intro_src/section4.html and Figure 25-16 of...

I have been working with a 2.8 (decayed over summer) micro curie cobalt-57 source testing a gamma camera. I would like to know if this made my risk for getting cancer higher ? My employers say l don't need to be worried.

I love Physics! I've been thinking about if... you were in a room with a window, bouncing a ball... and you were looking at another building where you could see a room with a person bouncing a ball, but ... their time was moving at half speed (Caused by gravitational time dilation only ( not...

Sorry for yet another one about the Higgs from a layman, and a perhaps tricky title. I was discussing with a friend and he came with this reasoning: Without the interaction with the Higgs field all the particles would be massless. Meaning that they would travel at the speed of light. Meaning...

Lets take a simple BJR transistor having an Rc. The Ic = beta*Ib, of course. But Ic=(Vcc-Vce)/Rc as well right? Now the confusion, does Ib cause Ic or is Ib possible without Ic (and thus no Vcc)? If we have Vcc and thus Vce than we shall have Ic thus we can have Ib=Ic/beta? What causes Vce, is...

Is the use of the term random a valid scientific explanation or just a pseudoname for unknown? I'm asking if it isn't essentially illogical to ascribe the existence of an event, (e.g the origin of the universe) to a random predecessor event. My humble understanding of logic adheres to a cause...

Hi, a friend and I were talking and a question came up about a delayed force. It goes like this: This is hypothetical obviously. You have the sun and the Earth pulling on each other because of gravity. (The force of the pull between them does not matter, it just has to be equal.) The sun and...