Blood oozing

[kjab3112]

1. What data have you performed regression on exactly?

2. What exactly is "data within the sources given"?

3. Do you have a random sample or not?

4. What independent variables are in your model?

Pierre

1. To develop the scatter I paired known mean values of base blood flows and then derived further data points on the mean reductions in peer reviewed published literature with the fixed points of blood loss given in each paper

2. As stated. These sources refer to separate studies data and how blood loss (either genuine or simulated) reduced blood flow in those specific arteries. Each study usually used a different amount of blood loss, I simply collated them to perform a scatter plot and subsequent regression using OpenOffice calc.

3. These are all means (with available standard deviations) which are based on a sample. It is not ethical to perform a true randomised control study so these cases are either a population mean or single case controlled samples. They are old papers when Doppler measurement of vessel flow was being devised and are often cited by 100+ later papers.

4. For independent variables I have assumed that blood loss is 100% of flow through that vessel. In physiological response to bleeding, there are vessel level changes that occur which act to reduce blood flow from that cut vessel. I have however ignored venous back bleeding from the organ which has been denuded of its blood supply. The reasoning for this is that once arterial flow has ceased, venous outflow from any capillary vessel is minimal.
I have assumed minimal blood loss from capillary skin level bleeding, this is due to the magnitude differences involved so can be reasonably ignored when looking at a short period of bleeding.

Hope that resolves your questions

Paul

[Joshua Rogan]

While I always naturally respect the arguments on JtR forums, it was nevertheless the opinion of Dr Bond that "no doubt the wound in the throat would cause almost immediate death" and of Dr Phillips that "death almost immediately followed the incision of the neck".

I've heard it suggested that, if the throat was cut right round (thus severing both vagus nerves) then the heart would stop beating immediately. Which may explain the doctors' statements. And affect the blood loss. If it's true, that is.... can any medical types confirm?

[Elamarna]

I very much doubt that death would have been instantaneous: see, for example, http://realfighting.com/unconsciousness_and_death.php

Agree. Real instantaneous death is very rare.


Steve

[Elamarna]

[QUOTE=Pierre;415867]

Wrong. If you want to estimate physical results you need individual data, not structural data.



If that text is respected it does not mean that Paulīs calculations are correct.



Exactly what is neccessary "base data"? Do explain.

Pierre

The data used has been collected from many years of research. It is used in the teaching of medicine.


I do understand that you want to understand if the data is robust and valid.


Flow rates are very well established and heavily documented academically.

Most of what you are asking will have been done in the sources Paul quotes.

I honestly think if you really want to understand it, you will need to read a great deal of that research.


Best wishes


Steve

[Sam Flynn]

Wrong. If you want to estimate physical results you need individual data, not structural data... Exactly what is neccessary "base data"? Do explain.

We're talking about the rate of flow of a fluid through a tube, in essence. Taking into account factors like the average rate of flow, the average diameter of the tube (which is what I meant by "base data"), you can calculate to within a good approximation as to how long it would take a given volume of fluid to drain out of the tube. In respect of blood flow, data such as these are obtainable from textbooks on physiology, whose information content has been compiled, revised and refined for several decades. This is particularly true in the case of the textbook which Paul cites as his source (Guyton).

If that text is respected it does not mean that Paulīs calculations are correct.

Indeed, so why not get yourself a physiology textbook and work it out yourself?

[John G]

Phillips report says only the left side was cut, far different from Nichols.
It just underlines that opinions of experts may be wrong.

If Phillips really meant pouring as we use the term, then death could not have been as quick as they suggested.


Steve

I very much doubt that death would have been instantaneous: see, for example, http://realfighting.com/unconsciousness_and_death.php

[David Orsam]

"Iīm planning to go on with the research and I know what data I need to prove who the killer was. There is only some very sparse data I need for this and it is probably not impossible to find." (Pierre, 17 December 2015)

Perhaps Paul has the data Pierre has long been looking for.

[Elamarna]

This isn't statistics, Pierre, it's physiology. Paul cited Guyton as the source of his figures, and it's a hugely respected text. There are other good textbooks (e.g. Ganong) where the necessary base data can be obtained, and anyone competent at mathematics should be able to extrapolate from them.

Sam to be fair to Pierre, and I am very often not, he is not a natural scientist and probably does not realise the data Paul is using is the result of many years of research on blood flow, data which is used in teaching medicine today.
So I do understand sort of why he asks, he does not know what the data is.

However you are of course correct, the data allows anyone with good mathematical skills to work out the figures.


Steve

[John G]

[QUOTE=Pierre;415867]

Wrong. If you want to estimate physical results you need individual data, not structural data.



If that text is respected it does not mean that Paulīs calculations are correct.



Exactly what is neccessary "base data"? Do explain.

Individual data?

[David Orsam]

Phillips report says only the left side was cut, far different from Nichols.
It just underlines that opinions of experts may be wrong.

If Phillips really meant pouring as we use the term, then death could not have been as quick as they suggested.

Perhaps he was actually trying to say "oozing profusely".

[Pierre]

[QUOTE=Sam Flynn;415864]

This isn't statistics, Pierre, it's physiology.

Wrong. If you want to estimate physical results you need individual data, not structural data.

Paul cited Guyton as the source of his figures, and it's a hugely respected text.

If that text is respected it does not mean that Paulīs calculations are correct.

There are other good textbooks (e.g. Ganong) where the necessary base data can be obtained, and anyone competent at mathematics should be able to extrapolate from them.

Exactly what is neccessary "base data"? Do explain.

[John G]

According to Dr Bond "the two main cuts appeared to be about 3 inches long...", which suggests less extensive neck injuries than were inflicted on Nichols.

[Elamarna]

While I always naturally respect the arguments on JtR forums, it was nevertheless the opinion of Dr Bond that "no doubt the wound in the throat would cause almost immediate death" and of Dr Phillips that "death almost immediately followed the incision of the neck".

Phillips report says only the left side was cut, far different from Nichols.
It just underlines that opinions of experts may be wrong.

If Phillips really meant pouring as we use the term, then death could not have been as quick as they suggested.


Steve

[Sam Flynn]

1. What data have you performed regression on exactly?

2. What exactly is "data within the sources given"?

3. Do you have a random sample or not?

4. What independent variables are in your model?

This isn't statistics, Pierre, it's physiology. Paul cited Guyton as the source of his figures, and it's a hugely respected text. There are other good textbooks (e.g. Ganong) where the necessary base data can be obtained, and anyone competent at mathematics should be able to extrapolate from them.

[David Orsam]

It has been argued over on JtR forums that she was technically alive for some time after discovery.

While I always naturally respect the arguments on JtR forums, it was nevertheless the opinion of Dr Bond that "no doubt the wound in the throat would cause almost immediate death" and of Dr Phillips that "death almost immediately followed the incision of the neck".