Áhrif "Shock effect" á bráð.

[Bowtech]

Svo kallað Shock effect á bráð.
Samkvæmt Rannsókn sem gerð var af 2 aðilum frá Noregi og Svíþjóð um áhrif Shock effect frá kúlu á bráð. . En hún var upphaflega gerð til að varpa ljós á þá staðhæfingu framleiðenda að Shock effect drepur.
Teknar eru nokkra kúlugerðir og borið saman hversu áhrifaríkar kúlurnar eru til veiða.

Niðurstaðan er það virðist vera algengur misskilningur og ranghugmynd á meðal veiðimanna að það sé högg (Shock effect) frá veiðikúlu sem drepur.
Eins og þegar dýr dettur niður á staðnum þá er það ekki af höggi kúlunar heldur er það að brot úr henni séu að lenda í taugaendum því detti dýrið niður, en að öðrum kosti þá hleypur það áfram og reynir að koma sér í burt á meðan það blæðir út og deyr vegna súrefnisskorts þar sem blóð er hætt að berast til líffæra og það örsakar lost. Það er það námkvæmlega sama sem myndi koma fyrir ef örvaoddur myndi lenda í taugabúnti og eða öðru þá er það eins.
Þeir sem gera þessa rannsókn eru: Jon Arnemoer dýralæknir og prófessor við 2 skóla í noregi og landbúnaðar háskóla í Svíþjóð en Sigbjorn Stokke er sérfræðingur við norska nátturfræðistofnun í Noregi
Hvet alla lesa þessa grein hérna fyrir neðan og endilega segið ykkar skoðun á þessu..
Það var búið að biðja mig um að þýða þessa grein en ákvað að skýra frá hver í raun niðurstaðan er þar sem það eru nokkuð mörg orð sem maður er ekki viss hvernig á færa yfir á ísl svo skilið sé.

Wound ballistics and the concept of “death by shock”
Sigbjørn Stokke & Jon M. Arnemo

The term “shock” is considered by many to be an important factor when comparing the killing
power of different cartridges and bullet types. Manufacturers of hunting ammunition
commonly declare that their bullets deliver tremendous shock upon impact and therefore have
superior killing power. Here we discuss this concept and conclude that there is no instant
shock effect in an animal hit by a bullet.

When comparing effectiveness of different types of bullets wound ballistics must be
considered. Wound ballistics is defined as the theory of interactions between a penetrating
projectile and living tissue. Wound ballistics includes only the primary (immediate) effects of
projectile penetration such as the wound, cavitations and effects on nerves. Secondary effects,
including blood loss, reduced blood pressure and decreased tissue oxygen delivery occur later.
Although a shock wave is generated when a high speed projectile penetrates tissue, it is
necessary to make a distinction between shock and pressure waves. Both waves occur when a
projectile penetrates tissue. A shock wave lasts in the order of microseconds, while a pressure
wave sustains for milliseconds. A shock wave is a type of sound wave (acoustic compression
wave) that passes through the body at a speed of about 1500 m/s. In wound ballistics, the
shock wave is generated by the projectile (as it ruptures tissue) and propagates in front of the
penetrating projectile. No substance is transported by such a wave. In contrast, a pressure
wave moves body tissue and therefore generates pressure changes as it propagates. A high
speed penetrating projectile dislodges and accelerates elastic tissue in a direction
perpendicularly to its forward motion creating a temporary cavitation behind the projectile
that is much larger than the projectile’s diameter. Thus, the forces of inertia on the tissue
create a pressure wave that propagates throughout the whole body of an animal. During this
process, tissue is compressed and stretched but strain energy rapidly forces the elastic tissue
back to approximately the original position.

So, how dangerous is this “shock” wave? There is a misconception that an individual could
instantly die from a high-speed bullet even if it barely touches the body. However, no
scientific proof for such instant shock-effects is ever described.

A penetrating bullet will cause a shock wave to propagate throughout the body. Nerves are
stimulated by shock waves and respond with increasing amplitude until they are fully
stimulated and cannot be stimulated further. However, nerves respond similarly whether the
stimulus is a shock wave or an external pressure. The target organ influenced by the nerve
impulse cannot tell whether the received impulse originated from internal or external
stimulation. It is therefore unlikely that an internal shock wave would generate a different
reaction than an external counterpart. A good example is that acoustic waves (with five times
the intensity of a shock wave generated by a bullet) can be used to break up kidney stones in
non-invasive procedures.

Body cells are also affected by shock waves and are damaged if bullet velocities are high
enough. However, cell damage occurs many hours after the passage of the bullet and the 2
effect is therefore not instantaneous. However, the mechanisms behind this cell damage are
not yet understood.

The misconception of instant death by shock has arisen because animals frequently are
instantly knocked down when hit by a bullet. This might happen with a central nervous
system (CNS) impact causing a total loss of motor function or as a result of mass impact
forces due to the formation of the temporary cavity. The rapid displacement of tissue mass
can brake bones or affect CNS and other sensitive organs so that the animal instantly faints
and falls like hit by a sledgehammer. If the impact causes a lethal bleeding the animal will die
before it regains consciousness and the hunter is left with the impression that the animal died
by some shock effect. A bullet fragment might also give the same reaction. The instant knock
down effect is therefore the result of a pure mechanical interaction.
Thus, we are left with two possible causes of death as a result of a penetrating projectile
(bullet or arrow):

1. Collapse of the circulatory system due to loss of blood
2. CNS trauma causing total loss of motor functions
The medical term “shock” represents a state of impaired oxygen delivery to the tissues of the
body as a result of reduced blood flow. Shock is never instant and develops over time. Thus
all animals belonging to category 1 will ultimately go into shock and die when blood loss,
blood pressure and oxygen delivery have reached critical levels. But this is no instant event
and it might take several seconds to some minutes before the animal is grounded.
We hope that this discussion will help to clarify some misinterpretations related to the concept
of so-called death by shock.

References:
Kneubuehl BP, Coupland RM & Thali MJ (2008) Wundballistik, grundlagen und
anwendungen. Springer Medizin Verlag, Heidelberg.
MacPherson D (1994) Bullet penetration: modeling the dynamics and the incapacitation
resulting from wound trauma. Ballistic Publication, El Segundo, CA
Sellier KG. & Kneubuehl BP (1994, 2001) Wound ballistics and the scientific background.
Elsevier.
Suneson A, Hanson HA & Seeman T (1990) Pressure wave injuries to the nervous system
caused by high-energy missile extremity impact: part I. Local and distant effects on the
peripheral nervous system. A light and electron microscopyic study on pigs. J. Trauma 30,
281-294.
Suneson A, Hanson HA & Seeman T (1990) Pressure wave injuries to the nervous system
caused by high-energy missile extremity impact: part II. Distant effects on the central
nervous system. A light and electron microscopyic study on pigs. J. Trauma 30, 295-306.
Suneson A, Hanson HA, Kjellstrom BT, Lycke HA & Seeman T (1990) Pressure waves
caused by high-energy missile impair respiration of cultured dorsal root ganglion cells. J.
Trauma 30, 484-488.
Wehner FP & Sellier K (1981) Shock-wave induced compound action potentials in the
peripheral nerve. Z. Rechtsmed. 86, 239-243. 3
Sigbjørn Stokke (PhD) is a researcher affiliated with the Norwegian Institute for Nature
Research, Trondheim, Norway
Jon M. Arnemo (DVM, PhD, Dipl. ECZM) is a veterinarian and professor affiliated with the
Hedmark University College, Campus Evenstad, Norway and the Swedish University of
Agricultural Sciences, Umeå, Sweden

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