Archery Ballistics

[Markdoc]

Re: Archery Ballistics

 

*looks around*

 

 

I think I'll just stay with the rules as given.

 

 

Me too: I don't actually WANT realistic combat in my games, even those that are "gritty". All I want are rules that encourage people to behave rationally (like seeking cover when being shot at).

 

Still, if other pople wish more detail - it's Hero system: detail away!

 

cheers, Mark

[Starwolf]

Re: Archery Ballistics

 

Sorry to jump in this late in the conversation. I can't quote hard science, but I am an avid hunter both with rifle and bow. The damage done is very different. For rifles what knocks an animal down is shock. When a bullet penetrates in addition to the hole, it makes tissue expand as it passes through which then collapses behind the bullet (Or fragments if the bullet splinters). Each channel causes this hydrostatic shock. The animal drops from this trauma. This is why you NEVER chase a wounded animal, if you get the adrenaline flowing the beast will run forever before succumbing. If you take the shot then move up slowly, usually the animal will move off a few yards then crawl under a bush or tree and lay down and expire.

 

Now a bow on the other hand kills by bleeding action. Modern broadheads are designed for sustained, accurate flight, and penetration. Once you score a hit the arrow hangs in the would channel cutting the surrounding tissue as the animal moves. Some arrows have heads designed with barb like wings that help the arrow to stay embedded. My father (and hunting companion) has a self healing archery target out behind his house that, according to the manufacturer, is supposed to simulate the density and penetration of a real deer. I am able to sink a broadhead about 12 inches on average into this target at 75 yards. In my experience I usually have to track my kill a bit farther when bow hunting over a rifle shot, but the difference is measured in yards. In 30 plus years of hunting I have only once dropped a buck in its tracks with a bow (a very lucky heart shot). And I have dropped a total of 2 bucks and 1 bull elk in thier tracks with a rifle. Overall I have probably bagged close to 50 big game animals through the years.

 

So in summary arrows do have less penetrating power overall, but in thier own way they are just as deadly at close range. I have seen deer jump out of the way of an arrow, so stalking and a silenced weapon can be important.

[BonHed]

Re: Archery Ballistics

 

Couple o' points:

 

First off the myth that arrow wounds are in some mystical way different from bullet wounds is, well, a myth.

 

 

There is something to be said for the sharpness of the object doing the cutting. A ragged wound caused by a dull blade will clot faster than a clean cut caused by a razor sharp blade.

 

The platelettes in the blood stream are better able to adhere to the more ragged edges of a wound caused by a dull blade. The sharper the blade, such as a razor or scalple, the longer it takes the platelettes to start congregating and forming the clot. That's why when one cuts ones' self shaving with a razor, it bleeds for a good long time.

 

I would imagine, however, that this is going to be more of a long term, rather than an immediate effect. Long term being a matter of minutes, rather than seconds.

 

And the brain certainly does play a role. Blunt trauma causes more shock to the body, which the brain has different methods for handling. Muscles will clamp down around severed blood vessels, and can prevent or lessen the blood flowing from a severed limb (this is, of course, only a very temporary effect; one had better get a tourniquette around that severed limb pretty quick). This happens automatically when the brain registers the shock of the cut. A particularly sharp blade may cut so cleanly as to produce less shock to the body; the brain may not register the wound correctly, and the proper signals may not be sent to the muscles around the wound to force them to clamp down.

 

Now this is all subjective. Lots of different factors can contribute to this scenario, and it doesn't always happen the same way for everyone, everytime. But there are different kinds of wounds, all of which affect the body in different ways.

[Eosin]

Re: Archery Ballistics

 

The easy answer is to refer to EMEDICINE.

 

Gunshot wounds (GSWs) have a much broader injury pattern due to several mechanisms [than Stab Wounds [sW]]. First, any structure directly in the path of the missile suffers a loss of integrity. Approximately 85% of abdominal wall GSWs penetrate the abdominal cavity, and 95% require a surgical procedure for correction. Injury also is caused by fragmentation of the bullet on impact.

 

The transfer of kinetic energy from the missile to surrounding tissue as it traverses its path creates injury in several unique fashions. Kinetic energy is directly proportional to the mass and the square of the missile velocity; impact velocity directly relates to the wounding potential of a projectile. Missiles are categorized by their velocity profile into low-, medium-, and high-velocity projectiles. The impact speed is affected by several factors, including target distance, missile velocity, missile mass, missile shape, and drag. A missile creates longitudinal and horizontal shock and shear waves as it traverses different media. These, in turn, lead to cavitation of surrounding structures. The temporary cavity formed can contuse and lacerate tissues, fracture vascular intima, and rupture large vascular conduits. Dependent upon the energy imparted by the missile, these injuries may extend a significant distance from the bullet track.

 

Your brain has little to do with clotting processes except in cases where you engage the flight or fight syndrome and begin dumping tremendous amounts of endogenous pressors into your blood stream. This may keep you alive a bit longer but at the end of the day you are still dead.

 

In my subjective, but educated, opinion the wounds and treatment for the two mechanisms of injury are basically equally leathal. Penetrating wounds to the abdomen or thorasic cavity are gonna require immediate surgery 80% of the time or death will rapdily follow the wound.... If not from profound shock, then from secondary infection (the colon is full of doodoo and the lungs aren't meant to be deflated. Your other options include the liver, heart, great vessels, or the ever so awesome ~ "dude, you got lucky. You should be dead.")

 

Gotta go to bed.

[Markdoc]

Re: Archery Ballistics

 

There is something to be said for the sharpness of the object doing the cutting. A ragged wound caused by a dull blade will clot faster than a clean cut caused by a razor sharp blade.

 

Sounds reasonable - but is not actually true, and we have 150 years of surgical experience to confirm this. The reason we use the sharpest possible blades (or lasers) in surgery is not to leave a clean edge, but to reduce the amount of collateral damage.

 

The platelettes in the blood stream are better able to adhere to the more ragged edges of a wound caused by a dull blade. The sharper the blade' date=' such as a razor or scalple, the longer it takes the platelettes to start congregating and forming the clot. That's why when one cuts ones' self shaving with a razor, it bleeds for a good long time.[/quote']

 

Again, sounds reasonable, but is untrue. Platelets adhere to the surface of cells via integrins. All that is necessary is an intact cell membrane expressing integrins (and yes, other receptors) and the "roughness" of the surface is, quite literally irrelevant. Platelets are very very flexible and will flow over surfaces ike mercury - but without integrin expression, they won't stick. And integrin expression is regulated at the level of individual cells and tissues, not systemically (good thing too, or we'd all be dead of internal blood clots).

 

If you've ever done microsurgery (and I have), you'll know that the finest blades humanity can produce leave a mess at the cellular level somewhat akin to cutting watermelons with a chainsaw. It's why we use lasers today, which can cut at a cellular level, where we can.

 

The reason your face bleeds a lot when you slice it with a razor, is because it's full of blood vessels, just under the surface (it's why it goes red when you overheat, whereas your stomach does not - at least to the same degree). Scrape it with asphalt (and I've done that too, back in my skateboarding days) and it will bleed every bit as freely, I promise you. The difference - and the reason we are surprised at how much blood there is after a shaving accident - is because you don't notice the cut as much as you do road rash.

 

And the brain certainly does play a role. Blunt trauma causes more shock to the body' date=' which the brain has different methods for handling. Muscles will clamp down around severed blood vessels, and can prevent or lessen the blood flowing from a severed limb (this is, of course, only a very temporary effect; one had better get a tourniquette around that severed limb pretty quick). This happens automatically when the brain registers the shock of the cut. A particularly sharp blade may cut so cleanly as to produce less shock to the body; the brain may not register the wound correctly, and the proper signals may not be sent to the muscles around the wound to force them to clamp down.[/quote']

 

Nope again. Muscle spasm and closing of the capilliary bed is triggered primarily via local systems (it is, in fact, initiated at a sub-cellular level, characterized by hypermetabolism, accelerated gluconeogenesis, increased fat oxidation, and negative nitrogen balance, all occurring within seconds after injury). You can, in fact, induce the exact same responses (with identical kinetics) in acephalic individuals (ie: which have no brains) or in deeply sedated humans, where there is almost no brain activity, or indeed, in muscle tissue where the nerves are totally destroyed, so that there is no feedback to the CNS at all (this happens in leprosy patients, where I am most familiar with it from clinical experience).

 

We are, of course, talking about the acute response to injury (what's sometimes called the "Ebb Phase": the brain does play a role in coordinating overall responses to trauma (thee "Flow Phase") - but this is well after the initial phase - it can last as long as a month. Shock is induced by the body's response to injury (or percieved injury: you can induce shock without any actual trauma) - it is not an essential part of the response or the cause of it, as indicated by the fact that an excited individual can respond normally (at the cellular and tissue level) to injury without suffering any shock.

 

Lots of different factors can contribute to this scenario' date=' and it doesn't always happen the same way for everyone, everytime. But there are different kinds of wounds, all of which affect the body in different ways.[/quote']

 

Now, THIS on the other hand is true. Other factors circulating in the body can greatly modify the effect of trauma. What matters is the degree of trauma, the location of the trauma and external factors such as adrenaline levels. What *doesn't* matter is whether it's slicing, crushing or piercing. A bullet in the butt and an arrow in the butt will induce a similar response, all things being equal, as will an arrow in the gut and a bullet in the gut.

 

cheers, Mark

[BonHed]

Re: Archery Ballistics

 

Again' date=' sounds reasonable, but is untrue. Platelets adhere to the surface of cells via integrins. All that is necessary is an intact cell membrane expressing integrins (and yes, other receptors) and the "roughness" of the surface is, quite literally irrelevant. Platelets are very very flexible and will flow over surfaces ike mercury - but without integrin expression, they won't stick. And integrin expression is regulated at the level of individual cells and tissues, not systemically (good thing too, or we'd all be dead of internal blood clots). [/quote']

 

Here's hat I learned when I studied human anatomy in college: platelets are sticky and adhere to the edges of objects they find inside a blood vessel (such as a cut, or a device implanted to strengthen a blood vessel wall). Once they have begun to stick to the surface, they then release chemicals that attract more platelets. They form fibrin chains that trap yet more platelets, eventually forming a clot.

 

http://www.besthealth.com/besthealth/bodyguide/reftext/html/cardio_sys_fin.html

 

http://en.wikipedia.org/wiki/Platelet (it's Wikipedia, so it must be taken with a grain of salt - no telling how accurate it is, but it does follow along with information found elsewhere)

 

So the smoother the cut, the longer it will take for the clot to form. A scalpel blade is going to leave a much smoother cut than one from a less sharp blade. Since a blood vessel is fairly elastic and small, let's use an analogy of something that we can wrap our heads around: plastic wrap. Cut it on the sharp metal edge provided on the box, and you get a smooth, clean cut. Tear it with your fingers and it deforms, ripping away in ragged chunks. Now try to fit the two sets of edges back together. Which set fits together with the least amount of gap? The one cut smoothly on the edge of the box.

 

Now sure, on the cellular level, both cuts are ragged, since neither breaks the bond holding the cells together. But there is more surface area exposed on the stretched, deformed edge. So in a blood vessel, this would mean more exposed collegen, so more platelets adhere.

 

The reason your face bleeds a lot when you slice it with a razor' date=' is because it's full of blood vessels, just under the surface (it's why it goes red when you overheat, whereas your stomach does not - at least to the same degree). Scrape it with asphalt (and I've done that too, back in my skateboarding days) and it will bleed every bit as freely, I promise you. The difference - and the reason we are surprised at how much blood there is after a shaving accident - is because you don't notice the cut as much as you do road rash.[/quote']

 

Yes, faces do bleed a lot; perhaps that wasn't the best example. So how about fingers? I've managed to cut my fingers on both well used pocket knives (still somewhat sharp but not honed) and scalpel blades fresh out of the package. Boy, did that scalpel cut bleed a lot longer than the pocket knife cut. Same amount of pressure applied, comperable wound sizes. The scalpel blade cut left almost no scar, while the pocket knife cut left quite the nasty one. I will say this, however: the scalpel cut healed a lot faster, and it didn't hurt nearly as much as the cut from the much duller pocket knife. Not as much collateral tissue damage to repair.

 

Now, how much of an effect does this have immediately in a combat situation? I dunno, I've never been shot a bullet or an arrow. Do people/animals die immediately from both? Yes. Is it possible to bleed to death from both? Yes.

 

In the end, what usually kills a person/animal is lack of oxygen to the brain; whether this is caused by a bullet or an arrow is moot. But I do believe that there is a difference in the effect of a wound caused by different objects, be they crushing, slicing, puncturing, be they caused by a wickedly sharp knife or a dull metal edge.

[Remjin]

Re: Archery Ballistics

 

Wow... real science!

 

Always good to have a surgeon on board, thanks for the incites. Now I'm going to happily go back to keeping my combats simple and uncomplicated with cinematics in mind, because all these facts are going to confuse me. Plus, they'd be really boring to use in play.

 

However, I do feel better informed, so thank you.

[Dog Soldier]

Re: Archery Ballistics

 

The reason for an arrow to be as sharp as possible is so that it'll penetrate as deeply as possible. The deeper the wound the more it'll bleed. Image an arrow with a flat disk on the end of the shaft exactly the same weight as a broadhead. Of course it's not going to have th aerodynamics so image both are fired at a range that just clears the bow. The broadhead penetrates flesh and bone deeper.

[Remjin]

Re: Archery Ballistics

 

...what about an arrow with a brass fist on the end? =)

[Markdoc]

Re: Archery Ballistics

 

Here's hat I learned when I studied human anatomy in college: platelets are sticky and adhere to the edges of objects they find inside a blood vessel (such as a cut' date=' or a device implanted to strengthen a blood vessel wall). Once they have begun to stick to the surface, they then release chemicals that attract more platelets. They form fibrin chains that trap yet more platelets, eventually forming a clot.[/quote']

 

Mostly true - apart from the "sticks to edges" bit. Cells don't *have* edges. Platelets *aren't* "sticky" (otherwise your blood would clot inside your vasculature) And platelets don't stick to collagen (If they did, they'd stick as soon as they entered your heart, which has plenty of exposed colagen) As stated before, platelets adhere via receptors (primarily integrins). It's a very specific process. Now integrins are not normally expressed on the inner wall of cells lining the blood vessel - but when the vessel is ruptured the platelets suddenly gain access to cells that *do* express it. "Roughness" has nothing to do with it: we're not talking about velcro here - it's a cell surface phenomenon and what defines how fast a clot forms is:

1: blood flow into the damaged area. More platelets, faster clotting.

2: the size of the hole. Rough or smooth, doesn't matter. When it comes to trauma, size counts. A big hole will not seal readily, simply because it takes time to fill it all with fibrinogen. And of course, if you have a big hole, time is usually something you don't have much of.

 

Cut it on the sharp metal edge provided on the box' date=' and you get a smooth, clean cut. Tear it with your fingers and it deforms, ripping away in ragged chunks. Now try to fit the two sets of edges back together. Which set fits together with the least amount of gap? The one cut smoothly on the edge of the box.[/quote']

 

Now you're changing gears. A big hole will take longer to plug - but then, I said that in my first post. "Roughness" doesn't matter. Size does. To take your plastic wrap analogy, instead of using your fingers, poke a hole in in with a sharp pencil. Now you have a "bullet hole" - which dispite having slightly raggy edges will actually fit together and seal nicely.

 

 

I've managed to cut my fingers on both well used pocket knives (still somewhat sharp but not honed) and scalpel blades fresh out of the package. Boy' date=' did that scalpel cut bleed a lot longer than the pocket knife cut. Same amount of pressure applied, comperable wound sizes. The scalpel blade cut left almost no scar, while the pocket knife cut left quite the nasty one. I will say this, however: the scalpel cut healed a lot faster, and it didn't hurt nearly as much as the cut from the much duller pocket knife. Not as much collateral tissue damage to repair.[/quote']

 

I've also cut myself with scalpel blades more times than I can count (never at work though - always when modelling). Scalpel cuts do bleed like billy-o, but then they are almost always deeper than cuts with blunter blades. When I have given myself a good cut with a knife (the bleeding'est cut I think I've ever had, I gave myself with a vegetable knife while cutting up yams for a thanksgiving dinner) they bleed as long and as freely. But yes - scalpel wounds - any slicing wound actually - will heal more cleanly than a ragged wound, simply because it's easier to fit the ends together: hence my earlier "collateral damage" comment.

 

 

Now' date=' how much of an effect does this have immediately in a combat situation? I dunno, I've never been shot a bullet or an arrow. [/quote']

 

But I have. And I have never bled so much as I did from one small bullet wound. I've seen other people shot too. Trust me, if you haven't seen someone shot through the chest, you haven't seen bleeding. I must admit I have never seen anyone shot with an arrow, though

 

In the end' date=' what usually kills a person/animal is lack of oxygen to the brain; whether this is caused by a bullet or an arrow is moot. But I do believe that there is a difference in the effect of a wound caused by different objects, be they crushing, slicing, puncturing, be they caused by a wickedly sharp knife or a dull metal edge.[/quote']

 

In the long term, yes. In the short term, no. In the short term, what counts is how big the wound is and (most of all) where it is. That's not my own opinion but that of trauma surgeons who have looked at (and treated) thousands of wounds caused by knives, bullets, broken glass and similar tools. I've got more experience and knowledge than most folks (I'm a doctor, a researcher and as of last month, full professor at a medical school) but I'm no surgeon and not a trauma specialist. In this case, I accept the judgement of those who are.

 

cheers, Mark

[Markdoc]

Re: Archery Ballistics

 

The reason for an arrow to be as sharp as possible is so that it'll penetrate as deeply as possible. The deeper the wound the more it'll bleed. Image an arrow with a flat disk on the end of the shaft exactly the same weight as a broadhead. Of course it's not going to have th aerodynamics so image both are fired at a range that just clears the bow. The broadhead penetrates flesh and bone deeper.

 

You got it! And the reason for a broadhead is that a wide deep wound bleeds more than a narrow deep wound.

 

cheers, Mark

[Dog Soldier]

Re: Archery Ballistics

 

You got it! And the reason for a broadhead is that a wide deep wound bleeds more than a narrow deep wound.

 

cheers, Mark

 

 

Thanks! Now I have to wonder why my spellchecker let "th" slide for "the" but changed "imagine" to "image" twice

[bigdamnhero]

Re: Archery Ballistics

 

Image an arrow with a flat disk on the end of the shaft exactly the same weight as a broadhead. Of course it's not going to have th aerodynamics so image both are fired at a range that just clears the bow. The broadhead penetrates flesh and bone deeper.

Believe it or not I have a good friend who, when younger, used to duct-tape pennies over the ends of arrow shafts and he & a buddy would shoot them at each other with compound bows. (I never said he was smart.) Got some nasty bruises, but that's about it.

 

...and as of last month' date=' full professor at a medical school[/quote']

Congrats! Also thanks [and rep] for the excellent discussion.

[BonHed]

Re: Archery Ballistics

 

Platelets *aren't* "sticky" (otherwise your blood would clot inside your vasculature) And platelets don't stick to collagen

 

"Platelets clump by binding to collagen that becomes exposed following rupture of the endothelial lining of vessels. Upon activation, platelets release adenosine-5'-diphosphate, ADP and TXA2 (which activate additional platelets), serotonin, phospholipids, lipoproteins, and other proteins important for the coagulation cascade. " (Source, http://web.indstate.edu/thcme/mwking/blood-coagulation.html)

 

"...at sites of vascular injury, endothelial cells are damaged or removed. This exposes collagen fibrils, to which platelets adhere with help from von Willebrand factor, a blood protein synthesized by endothelial cells." (Source: http://64.233.167.104/search?q=cache:dHOmZhr86RQJ:www.pik-potsdam.de/~stefan/Publications/Nature/paillardn%26v.pdf+collagen+platelet+activator&hl=en&gl=us&ct=clnk&cd=10)

 

"Collagen and the GpVI-specific platelet activator collagen-related peptide (CRP-XL) stimulated NO synthesis, as evidenced by increased [(3)H]L-citrulline production, and cyclic GMP (cGMP) formation. After platelet activation by collagen and CRP-XL was normalised,..." (Source: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=16113831&dopt=Abstract)

 

God, I love the internet. I'm sure I can come up with some more sources, but I think three is an acceptable number for corroboration (Google came up with about 342,000 entries for "collagen platelet activator").

 

Perhaps "sticky" was not the best word to describe platelets, but I couldn't think of a better way to describe something that adheres to the surface of another thing. Plus, I saw it used in reference to platelets, so I figured it was safe.

 

I've got more experience and knowledge than most folks (I'm a doctor' date=' a researcher and as of last month, full professor at a medical school) [/quote']

 

Against my better judgement, I feel I must comment on this last statement. There is a major misconception among some learned individuals that what they say must be true, and that statements made by those with "lesser" knowledge cannot possibly be true.

 

I had a biology professor who swore up and down that the Punett Square was invented by a Frenchman, and that it was pronounced "Pun-ay". He adamantly refused to admit that he was wrong, even when it was pointed out to him, from the text from which he was teaching, that it was invented by an Englishman, Reginald Punett.

 

I had a physiology professor claim that the Rx symbol came from the Eye of Horus, whom he claimed was the Egyptian god of medicine. He drew the "Eye" on a chalkboard; it resembled the Rx symbol (it may have been something to represnt Thoth, whom the Egyptians recognized as the creator of all sciences, including medicine), but was definitly not the Eye of Horus. After class, I drew for him the correct Eye of Horus, and explained a little about Egyptian mythology. He of course did not believe a word of it. I did not at that time have any sources to document this, but was confident that I knew something of what I spoke.

 

So in these cases, I, a humble student, was correct, while the professors, with advanced degrees, were wrong. And further, neither of these two professors was willing to admit that they had made a mistake.

 

Congratulations on your professorship, I do understand that it is a very prestigious honour that requires tremendous study, knowledge, and experience. My father is a professor of Biochemistry, and it is from him that I learned to defend statements that I make where I believe that my knowledge is accurate, and gained the awful habit of not being able to let things go. I curse him daily for it.

 

And I promise that this is absolutely the final post I will make on the subject of platelets and blood clotting. The horse is dead, let's burry it.

[Eosin]

Re: Archery Ballistics

 

God, I love the internet. I'm sure I can come up with some more sources, but I think three is an acceptable number for corroboration (Google came up with about 342,000 entries for "collagen platelet activator").

 

Perhaps "sticky" was not the best word to describe platelets, but I couldn't think of a better way to describe something that adheres to the surface of another thing. Plus, I saw it used in reference to platelets, so I figured it was safe.

 

The most interesting part to me was that they back up everything Markdoc said. We tend to use rough terms to describe things in concepts that most people will understand, hence words like "thinning blood" and "sticky platelets." It works well until someone tries to dig too deep into what that really means or uses them in extensions of what would seem to be logicial conclusions.

[BonHed]

Re: Archery Ballistics

 

The most interesting part to me was that they back up everything Markdoc said.

 

They do not back up the point with which I had contention, and that was his statement that I quoted.

 

Technically, I didn't break my promise.

[Remjin]

Re: Archery Ballistics

 

My head hurts and my nose is bleeding... and I don't have any arrows, scalpels, or knives near me. And it won't stop.

 

Thanks, guys. =) I think I hurt my brain... erp... me no think so good now.

[Markdoc]

Re: Archery Ballistics

 

God' date=' I love the internet. I'm sure I can come up with some more sources, but I think three is an acceptable number for corroboration (Google came up with about 342,000 entries for "collagen platelet activator").[/quote']

 

Yep, and if you carefully parse those references, you will find that platelets bind poorly - if at all - to collagen itself, but instead bind to an integrin ligand (formerly and still often called von Willebrand factor, now known to be a famiy of related genes referred to as platelet membrane glycoprotein ligands, or PMGLs). To be fair, a decade or two ago, it *was* believed that platelets bound directly to collagen - that's why you find that statement in your first reference, which is from 1989: the age of the dinosaurs in terms of cell biology.

 

But as we now know, and as I noted previously, this process actually proceeds via very specific ligands and these ligands are expressed on a variety of tissues - including some (but not all) some forms of collagen and on other cells. Control of these ligands is very tissue specific and very tightly regulated and they can be rapidly upregulated in response to a variety of cellular release signals. Think of the collagen as providing a basic skeleton, onto which (as it is laid down) cells place "this goes here" and "press this button in case of emergency" labels. Platelet-activating ligands are not expressed inside the vasculature*, even though there is plenty of exposed collagen there. This is perhaps a more esoteric point than we need discuss here, but it serves as notice that finding articles on the internet is *extremely* useful (I couldn't work without it, these days) - but some caution is needed in interpreting them. This is something I have to hammer into graduate students, who all too often regurgitate chunks of text they don't fully understand (that's not intended to apply to you, btw: it's a general complaint).

 

There's a general, relatively non-technical overview of the process on Mike Berndt's group website at http://www.cvr.net.au/research/vascularbio.htm - he's considered a leading expert on this question.

 

In hindsight, I suppose, for general use, "binds to collagen" and "binds to ligands often found on some types of collagen (and some cells)" is close enough. It's not like we're in class: it's just that on technical topics like this, my get-it-exactly-right response kicks in: result of too much association with scientists, I suppose

 

Against my better judgement' date=' I feel I must comment on this last statement. There is a major misconception among some learned individuals that what they say must be true, and that statements made by those with "lesser" knowledge cannot possibly be true.[/quote']

 

That's fair enough - I'm usually a little cautious about bring my qualifications forward, and did so only to show I have some idea of what I am discussing. But note that I have never said "I say this, therefore it must be true" - no real scientist would ever use that argument. Personally I delight in puncturing people who take such pompous approach, so I could hardly object to your comment.

 

And I promise that this is absolutely the final post I will make on the subject of platelets and blood clotting. The horse is dead' date=' let's burry it.[/quote']

 

Fair enough - it doesn't have much to do the original discussion, but then that's the boards for you!

 

cheers, Mark

 

*Actually in some cases this does happen - some rare forms of Aortic Stenosis, for example.

[bigdamnhero]

Re: Archery Ballistics

 

Hey, no need to apologize, either of you. I for one have really enjoyed the discussion.

(The parts I could follow anyway. My head starts hurting after awhile and I have to go lie down.)

[Remjin]

Re: Archery Ballistics

 

... and bravo to both of you for keeping it civil and not taking things personally. Despite my jokes, I did find it enlightening, if a bit technical for my tastes in gaming. =)