Bioelectromagnetics

Lucianarchy said:
"Peter Zwamborn, who led the TNO team that produced the report, says he cannot explain the effect but adds that the findings have forced him to re-evaluate his view of cellphones. "Now I see that electromagnetic fields do something to humans, but what bothers me is that I cannot understand it," he told New Scientist." http://www.newscientist.com/news/news.jsp?id=ns99994225
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From a cursory reading of your link, it doesn't seem as though the study was "blinded". Certainly I can believe that people who consider such radiation to be dangerous could then exhibit such symptoms of stress such as headaches and cognitive disfunction when compelled to spend time near a transmitter.

If however the study was blinded with neither the people conducting the study nor the participants should know whether a particular transmitter is operating. I cannot tell from the full paper, my Dutch isn't sufficiently good.
 
MRC_Hans said:
But exactly because the internal conductivity of the body is quite good, the ability for external fields to produce potentials is seriously inhibited.

The conductivity of the body is far from lossless, but the overall resistance of a human body is in the order of 100-300 Ohms. The capacitance of a human body to an overhead wire is complex to calculate, but it is certainly less than 100pF. This gives a very high impedance to a 50Hz signal (obviously, or the energy loss in HT lines would be unacceptable), so the potential across a given body part will be very low indeed, even in the presense of a quite high external field, because the high conductivity of the body basically shorts out the field. If we are talking about such a small part of the body as a cell wall, the potential must be very low indeed.

Hans
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Hold on, Hans, when did you ever measure the conductivity of saline body fluids? We did and found some surprising results: the fluids at 0.9 percent conduct with virtually no loss of field strength and the fields do not fall off with distance, but are more or less the same at every part of the body (More on this as we get into technicalities). We then tried to see if the conductivity changed with salinity, and it showed a trend that at around 0.9 percent the conductivity was maximal, as if Nature had chosen that particular salinity in body fluids for its conductive effectiveness. Remeber also that these body fluids constitute 60-80 percent of total body mass, and can act as an important capacitor: we humans are like insulated bags of salty water! This capacitance can stay around inside the body for some time, as people who walk across nylon carpets discover when they grab a metal door handle. Ouch!
 
"Suppressed EPA Report: EMFs Present a Cancer Risk

Power-frequency electromagnetic fields (EMFs) should be considered arisk factor for childhood cancer, staff at the Environmental Protection Agency(EPA) concluded in 1994. This conclusion appears in a report which was sup-pressed by EPA’s senior managers and never released to the public.The report, recently obtained by Microwave News, reveals that analysts atEPA’s Office of Research and Development (ORD) recommended that: “[T]heapparently real association of disease with surrogates of prolonged magneticfield exposure has been established, so that it must be considered as one riskfactor for [cancer].” " http://www.microwavenews.com
 
cogreslab said:
Hold on, Hans, when did you ever measure the conductivity of saline body fluids?

When I worked with EKG recording equipment.

We did and found some surprising results: the fluids at 0.9 percent conduct with virtually no loss of field strength and the fields do not fall off with distance, but are more or less the same at every part of the body (More on this as we get into technicalities).

Exactly! Because of the low resistance the field is the same. But you do not measure conductivity by measuring the field (or, you could, indirectly, by measuring the magnetic field, but that was evidently not what you did. You were measuring an open-ended conductor.

We then tried to see if the conductivity changed with salinity, and it showed a trend that at around 0.9 percent the conductivity was maximal, as if Nature had chosen that particular salinity in body fluids for its conductive effectiveness. Remeber also that these body fluids constitute 60-80 percent of total body mass, and can act as an important capacitor: we humans are like insulated bags of salty water!

Capacitance has nothing to do with volume. Capacitance is between two plates, where we can be one. The size of the capacitance is determined by the area of the plates and the distance between the plates (and the dieletricity constant of the intervening medium).

This capacitance can stay around inside the body for some time, as people who walk across nylon carpets discover when they grab a metal door handle. Ouch!

No, the capacitance does not stay inside the body for any amount of time. The capacitance is always there, but its value varies with your distance to other conducting objects (which act as the other plate). What can stay for some time on your body capacitor is CHARGE. And this is actually interesting: The charge you build up walking across a carpet in a dry room results in a field many times that of an overhead HT line.
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Hans
 
The Don said:

From a cursory reading of your link, it doesn't seem as though the study was "blinded". Certainly I can believe that people who consider such radiation to be dangerous could then exhibit such symptoms of stress such as headaches and cognitive disfunction when compelled to spend time near a transmitter.

If however the study was blinded with neither the people conducting the study nor the participants should know whether a particular transmitter is operating. I cannot tell from the full paper, my Dutch isn't sufficiently good.
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Dunno, I think that ethical considerations preclude blinding in a study that might result in some deliterious effect.
 
http://66.102.11.104/search?q=cache:yIC8NNHLj_8J:www.essex.ac.uk/psychology/psycholo....pdf+essex+electromagnetic+double+blind&hl=en

"[...]Following this phase of the study, a double-blind experiment will beconducted to assess whether exposure to RF-EMF, as generated by a standard GSM base station,will elicit symptoms for people meeting the inclusion and exclusion criteria for EHS. A wide rangeof physiological, psychological, and cognitive indices will be measured during actual and shamexposure in addition to acute health symptoms. Each participant in the double-blind exposurestudies will also take part in an open provocation study in which they will be asked to explicitlyassociate their symptoms with the different exposure conditions.[...]"
 
I think it may be helpful to know that the reduction to 100uT in the NRPB's ELF exposure guidelines (from a massive 1600 uT previously) does no more than bring them to the same level as the recommendations of ICNIRP. The NRPB did this largely because it looked ridiculous for the NRPB to offer advice so disparate from that of ICNIRP, thereby previously bringing both recommendations into question. Even the new level is not addressing the main issue opf nonthermal effects, and that is why Henshaw wants the guidelines brought down to the consensus level at which epi studies begin to see an elevated incidence of childhood leukaemia. This is not an impossible target in practical terms, and is also in line with the EC recommendation of exercising the Precautionary Principle.
 
To MRC Hans: I assume EKG is electrocardiogram equipment. This measures current amplitudes not fields, does it not? We were measuring not currents but fields as expressed in units of Volts per metre, i.e. the voltage at x distance between two plates separated by some sort of insulator, in this case air.
 
To MRC Hans: there is inevitably a relationship between the volume of the dielectric between the two plates in your solid capacitor and its capacitance, if you think about it: the more volume of whatever material lies between your two plates, the greater the capacity of that passive component to resist a passage of current. Capacitors store current in the sense that they resist passage until a certain level is reached. You can get a nasty shock from a TV set long after it has been disconnected from the mains.

Regarding your point about charge, such charges are electrostatic when we are discussing alternating currents. I can see a case for saying that highly charged biota are not affected while they are acting as capacitors (like birds on a powerline): the effects only cause damage when there is an actual flow of current, say to earth, or a field external to the material. alternating
 
cogreslab said:


Snip*
....We did and found some surprising results: the fluids at 0.9 percent conduct with virtually no loss of field strength and the fields do not fall off with distance, but are more or less the same at every part of the body (More on this as we get into technicalities). We then tried to see if the conductivity changed with salinity, and it showed a trend that at around 0.9 percent the conductivity was maximal, as if Nature had chosen that particular salinity in body fluids for its conductive effectiveness.

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Are you talking about intracellular fluid, extracellular fluid, CSF specifically or is this an average figure?

I don't understand "showed a trend that at around 0.9 percent the conductivity was maximal, as if Nature had chosen that particular salinity in body fluids for its conductive effectiveness",

Action potentials in neurones and muscle cells depend on an exchange of ions between the extracellular fluid and intracellular across the cell membrane, and the ionic composition of the intracellular and extracellular fluids differ.
 
To MRC Hans: Hans I am going to be pretty busy the next few days, so I am asking my physicist, Chris, who did the conductivity expt. to continue this dialogue (also though I know he is pretty busy too doing a study on the effect of static magnetic fields on bacterial movement). I am not dodging the issue, but am up against deadlines to prepare some papers for a forthcoming conference. A quick and dirty answer to your question: we were looking at the way extracellular bathing fluids carry information from the brain to the glycoproteins on cell surfaces, and the role of extracellular Ca2+ which is a pretty universal second messenger.
 
cogreslab said:
To MRC Hans: I assume EKG is electrocardiogram equipment. This measures current amplitudes not fields, does it not? We were measuring not currents but fields as expressed in units of Volts per metre, i.e. the voltage at x distance between two plates separated by some sort of insulator, in this case air.
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You assume right. It does not matter. Fields and current are inextricably connected. Ohm's law, you know...........

Hans
 
cogreslab said:
To MRC Hans: there is inevitably a relationship between the volume of the dielectric between the two plates in your solid capacitor and its capacitance, if you think about it: the more volume of whatever material lies between your two plates, the greater the capacity of that passive component to resist a passage of current. Capacitors store current in the sense that they resist passage until a certain level is reached. You can get a nasty shock from a TV set long after it has been disconnected from the mains.

Excuse me, but this is mumbo jumbo. We are not talking about he volume of the dielectric, we (you) are talking about the volume of the conducting plate. Capacitors do not store current, they store charge.

Regarding your point about charge, such charges are electrostatic when we are discussing alternating currents.

Good, you noticed that one. ;)

I can see a case for saying that highly charged biota are not affected while they are acting as capacitors (like birds on a powerline): the effects only cause damage when there is an actual flow of current, say to earth, or a field external to the material.

Right! There needs to be a current. And therefore you field measurements are irrelevant.
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Hans
 
cogreslab said:
To MRC Hans: Hans I am going to be pretty busy the next few days, so I am asking my physicist, Chris, who did the conductivity expt. to continue this dialogue (also though I know he is pretty busy too doing a study on the effect of static magnetic fields on bacterial movement). I am not dodging the issue, but am up against deadlines to prepare some papers for a forthcoming conference. A quick and dirty answer to your question: we were looking at the way extracellular bathing fluids carry information from the brain to the glycoproteins on cell surfaces, and the role of extracellular Ca2+ which is a pretty universal second messenger.
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No problem, I'll be gone for over a week anyway.

Hans
 
cogreslab said:
Mulder: someone drew attention to his infamous Q and A site. I have read this carefully many times, and he has had to withdraw at least one response as a result of my protests. The site gives a very biased view of the literature in my opinion, and remember that at Wisconsin is situated the US Navy's enormous ELF transmitter for communicating with submarines, an installation which has kept researchers there in business for decades. Some say that Mulder is actually funded by the US Navy, but I have no proof of this.
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I sent an email regarding the above claims to Professor Moulder, Professor of Radiation Oncology, Medical College of Wisconsin the author of the website referenced and requested permission to post some of his replies.

Point 1

cogreslab stated:

I have read this carefully many times, and he has had to withdraw at least one response as a result of my protests

Moulder's response:

The above is news to me. The only mention of Coghill in the Powerline FAQ is to his 1996 paper that claimed that power-frequency electric fields caused childhood leukemia. No other published studies have shown such an effect.

Do you dispute Professor Moulder's response and if so can you provide any corroborating evidence?


Point 2

cogreslab stated:

remember that at Wisconsin is situated the US Navy's enormous ELF transmitter for communicating with submarines, an installation which has kept researchers there in business for decades.

Moulder's response:

That site is about 400 miles north of us, and as far as I know it has not been a source of research funding in over 20 years.

Do you dispute Professor Moulder's response and if so can you provide any corroborating evidence?


Point 3

cogreslab stated:

Some say that Mulder is actually funded by the US Navy, but I have no proof of this

Moulder's response:

I am not funded by the Navy and I never have been -- I work at a university where funding sources are public knowledge.

Do you dispute Professor Moulder's response and if so can you provide any corroborating evidence?



(Edited because I left the sin out of Wisconsin.)
 
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