effect of EMF on human being

8/10/2019 effect of EMF on human being

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1

By

Mohammed Osama Abdel Rahman

El Samadony


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Preface

There is much public concern about the issues surrounding the

effects of electromagnetic fields on health in particular, the

potential health effectsofnewcommunication technologies such

as mobile telephones. This report extensively describes what

electromagnetic fields are, where they are found, and what is

being done to investigate their potential for affecting our health.

There are maximum exposure limits that are reviewed in the

light of scientific researches.__________________________

2


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CONTENTS

Chapter1 Introducton!!!!!!!!!!!!!!!!!!!"" #

1.1 Overview

1.2 Thegrowingconcern !

Chapter$ Characterstcs of Electroma%netc felds !!!!!!"! &2.1 "hysics of #$%s &

2.2 Theelectromagnetic spectrum '

Chapter' Sources of Electroma%netc feld !!!!!!!!!!""" 1(

(.1)atural sources 1*

(.2 $an+made sources 1!

Chapter) EM* Impact on En+ronment!!!"""!!!!!!!!"" $) .1 -uman being 2

.2 nimals 2/

.( 0egetation 2' . uatic ife (*

Chapter# Standards and ,udelnes !"!!!!!!!""!!!!""""" '1

References!!!!!!!!!!!"!"!!!!!!!""!!!!""""" '#

(


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A--RE.IATIONS

E/* #xtremely ow %reuency

EM* #lectromagnetic %ield

ICNIRP 3nternational 4ommission on )on+3oni5ing 6adiation

"rotection

IEEE 3nstitute for the #lectric and #lectronic #ngineersNIR )on+3oni5ing 6adiations

R* 6adiofreuency

0. 7ltraviolet

2O 8orld -ealth Organi5ation


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Chapter1

INTRO30CTION

1"1 O+er+e45

6ecentyearshaveseenanunprecedentedincreaseinthenumberand

diversityofsourcesof electricandmagneticfields9EM*:usedfor

individual,industrialandcommercialpurposes. ;uchsourcesinclude

televisions,radios,computers,mobilecellularphones,microwave

ovens, radarsandeuipmentsusedinindustry,medicineandcommerce.

llthesetechnologieshavemadeourlifericherandeasier.$odern

societyisinconceivable withoutcomputers,televisionandradio.$obile

phoneshavegreatlyenhancedtheabilityof individualstocommunicate

witheachotherandhavefacilitatedthedispatchofemergency medical

andpoliceaidtopersonsinbothurbanandruralenvironments.6adars

ma.

;imultaneously,thesetechnologieshavebroughtwiththemconcerns

aboutpossiblehealth ris


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Thereisalsoconfusionaboutthebiologicaleffectsofnon-ionizing

radiations9e.gradio waves,microwaves,etc.:versusionizingradiations

suchas?+raysandgammarays =1>.

Theconflictbetweenconcernsaboutpossiblehealtheffectsfrom

exposureto#$%andthe developmentofelectricitysupplyand

telecommunicationsfacilitieshaveledtoconsiderable economic

conseuences.%orexample,electricalutilitiesinmanycountrieshave

hadtodivert highvoltagetransmissionlinesaroundpopulatedareasand

evenhalttheirconstruction.The installationofbasestationsformobile

telephonesystemshasbeendelayedorhasmet oppositionfromthe

publicbecauseofconcernsthatthe6%emissionsfromthesebase

stationsmightcausecancerinchildren.3nthe7nited;tates,for

example,/@ofthetotal numberofbasestationsneededhaveyettobe

constructed =1>.

$easurestosignificantlyreduceelectricandmagneticfieldsinthe

environment,belowwhatisnowcommonlyaccepted,arecostly.3thas

beenestimatedthatconcernsabout#$%and healtharenowcostingthe

7nited;tateseconomyaloneabout0S6 1bllonannually. -owever,

ifunacceptablehealthris.

1"$ The ,ro4n% Concern5

3n the last two decades, awareness has increased for this health ha5ard

problem and many institutions both public and private, expressed great

interests in the electromagnetic fields impact on environment as a global

issue and the human health as specific issue, resulting in a more precise

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definitions for the problem and standards that ensures its elimination or

reduction.

ll over the world, numerous studies have been carried out on the

possible effects of electromagnetic fields on humans, animals, plants and

cell or tissue cultures, and a series of large+scale epidemiological surveys

has also been conducted.

Aased on these research results and upon evaluations of biological

effects that have been established to have health conseuences, The

3nternational 4ommission on )on+3oni5ing 6adiation "rotection

934)36": developed a guidline for emf exposure limits =2>.

Bisparities in #$% standards around the world have caused increasing

public anxiety about #$% exposures from the introduction of new

technologies. Therefore, the 8orld -ealth Organi5ation 98-O:

commenced a process of harmoni5ation of electromagnetic fields 9#$%:

standards worldwide. %uture standards will be based on the results of the

8-OCs 3nternational #lectromagnetic %ield "roDect =2>.

&


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Chapter$

C2ARACTERISTICS O*

E/ECTOMMA,NETIC *IE/3S

$"1 Physcs Of EM*s5

8hen current flows in a wire, there is also a magnetic field generated

around it, which is the fundamental concept behind an electromagnet =(>.

This magnetic field radiates away from the wire in a circular fashion 9%ig.

1:. The combination of these two fields is what we call an

electromagnetic field 9#$%: =>. The electric field describes the force

created by electric charges, and the magnetic field describes the force

caused by moving charges in the form of electric current.

Fig. 1 Electromagnetic field around a conductor [4].

#lectric fields are produced by voltage and increase in strength as the

voltage increases. The electric field strength is measured in units of volts

per meter 90Em:. $agnetic fields result from the flow of current through

wires or electrical devices and increase in strength as the current

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increases. $agnetic field strength is usually measured in units of ampere

per meter 9 m1:. related uantity is magnetic flux density, measured

in tesla 9T:. The other unit freuently seen in the literature is milligauss

91* mF G 1 HT: =>.

The electric and magnetic fields that combine to form an electromagnetic

wave travel at right angles to each other and to the direction of motion. 3n

following figure 9%ig. 2:, imagine this electromagnetic wave front

traveling to the right of the page. The electric field 9Ejjjjjjjjjjjjjj

: in this illustration

consists of waves that rise and fall in a vertical plane, while the waves of

the magnetic field 9Hjjjjjjjjjjjjjjjjjj

: vibrate bac< and forth on a hori5ontal plane. These

waves, vibrating at right angles to each other, are inseparable and cannot

be defined individually. 3n other words, an oscillating field of electrical

energy will always create a magnetic field, and a moving magnetic field

will always create an electrical fieldI one causes and depends on the

other, and, together they form electromagnetic radiation =(>.

Fig. 2 A schematic view of an electromagnetic field propagating along the Z-axis.

he electric Ejjjjjjjjjjjjjj

and magnetic Hjjjjjjjjjjjjjjjjjj

fields oscillate in the x-! plane

and perpendicular to the direction of propagation ["].

'


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3n general, the electricity supply produces undistorted sinusoidal

waveforms with a freuency of *+!* -5. -owever, in some situations

the #$%s may contain additional freuency components called

harmonics, which are multiples of the fundamental freuency.

#lectric fields are shielded or wea


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at an enormous speed, the speed of light. The freuency simply describes

the number of oscillations or cycles per second, while the term

wavelength describes the distance between one wave and the next.

The freuency of an electromagnetic wave is simply the number of

oscillations which passes a fixed point per unit of time. 3t is measured in

cycles per second, or hert5. One cycle per second euals one hert5 9-5:.

arge divisions commonly used to describe radio freuency 96%: fields

include the


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ultraviolet 970: radiation, visible light and ?+ray radiation.

#lectromagnetic waves at low freuencies are referred to as

Kelectromagnetic fieldsK and those at very high freuencies are called

Kelectromagnetic radiationsK. ccording to their freuency and energy,

electromagnetic waves can be classified as either Kionizing radiationsK or

Knon-ionizing radiationsK 9)36: =>.

a7 Ion8n% radatons5

The freuency of ioni5ing radiation is measured in millions or

trillions of hert5 9cycles per second:. The energy contained in a

given photon is proportional to its freuency, which means that the

higher the freuency, the higher the energy. The tremendous photon

energy of ?+rays and gamma rays 9because of their extremely high

freuencies: is capable of changing the internal structure of atoms

and molecules, as well as being immensely penetrating. This is the

sort of radiation we associate with radioactive substances such as

uranium, radium, and radiation emitted during atomic and

thermonuclear explosions. 3oni5ing radiation has sufficient energy

to cause actual chemical changes to ta.

b7 Non9on8n% radatons5

)on+ioni5ing radiations is a general term for that part of the

electromagnetic spectrum which has photon energies too wea< to

brea< atomic bonds. They include ultraviolet 970: radiation,

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visible light, infrared radiation, radiofreuency and microwave

fields, extremely low freuency 9#%: fields, as well as static

electric and magnetic fields.

#ven high intensity )36 cannot cause ioni5ation in a biological

system. )36, however, have been shown to produce other

biological effects, for instance, by heating, altering chemical

reactions or inducing electrical currents in tissues and cells=>.

Fig. 5 Electromagnetic spectrum,!pes of E#$ adiation.

1(


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Chapter'

SO0RCES O* EM*s

The sources of power freuency #$%s are divided broadly into those

produced by natural processes and those generated by human activity.

)aturally occurring #$%s arise from electrical processes associated with

the #arth and the atmosphere. 3n most environments the dominant sourceof exposure is that associated with the generation, transmission and use of

electricity. "eople are exposed directly through the use of electrical

appliances or euipment, or incidentally through wor. The proportion of each type of radiationemitted by the sun is shown in the diagram 9%ig. !:J

;everal measurements made in high uote atmosphere show that a

surface of 1 cm2, adsorbing solar energy perpendicularly to the solar rays,

adsorbs a heat uantity of 1'/( calorie for each minute. This number is

said solar constant. Aeing 1calorie G 1/ Doule the solar constant in the

3nternational ;ystem is given by 1(/* Noule per m2and per sec. These

1


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data corresponds to an electrical field of &** 0Em and to a magnetic field

of 2. microtesla. The centre of the spectrum of the solar radiation is

given by a wavelength of 1* nm corresponding to green light =(>.

Fig. 6 Electromagnetic radiation from the sun.

'"1"$ Electrc and ma%netc feld of the earth5

;tatic electric and magnetic fields 9constant fields: of significant field

strength have always existed on this planet.

The movement of air in the atmosphere and the ionising effect of cosmic

radiation in the higher regions, the ionosphere, create a field of direct

electric current between the surface of the #arth and the ionosphere.

7nder normal weather conditions, the field strength near the ground is

around 1**+** 0Em, whereas it can rise to 2*,*** 0Em 92*


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strengths can occur in the vicinity of lightning 9up to 1 T, which can cause

heart failure in humans:. ;mall variations in flux density are induced by

the solar wind, which distorts the earthCs magnetic field due to its streams

of charged particles. %urthermore, global storm activity also results in

high+freuency components within the magnetic field. -owever, these are

so small that at * -5 the alternating field component is merely 1*+!T

=&>.

Fig. 7 atural electric 'direct( and magnetic 'constant( fields [/].

'"$ Man9Made Sources5

'"$"1 Po4er lnes5"ower transmission lines bring power from a generating station to an

electrical substation. "ower distribution lines bring power from the

substation to your home. Transmission and distribution lines can be either

overhead or underground. Overhead lines produce both electric fields and

magnetic fields. 7nderground lines do not produce electric fields above

ground but may produce magnetic fields above ground.

1!


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Power transmission lines5 -igh voltage lines in most of the world

have a voltage of 1(2


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Fig. #agnetic $ield from a +33-5 ransmission 0ine

#easured Ever! + #inutes for 2 6ee=>.

Power distrib!tion linesJ Typical voltage for power distribution

lines ranges from to 2 .

Power s!bstations" 3n general, the strongest #$% around the

outside of a substation comes from the power lines entering and

leaving the substation. The strength of the #$% from euipment

within the substations, such as transformers, reactors, and capacitor

ban


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substation fence or wall, the #$% produced by the substation

euipment is typically indistinguishable from bac.

#able 1 !pical magnetic field strength of household appliances at various distances [7].

Electrc applance ' cm dstance

:;T7

'( cm

dstance :;T7

1 m dstance

:;T7

Refr%erator *. 1.& *.*1 *.2 Q*.*1

Colour T. 2. + * *.* 2 *.*1 *.1

Portable rado 1! ! 1 Q *.*1

Iron / (* *.12 *.( *.*1 *.*(

3sh4asher (. 2* *.! ( *.*& *.(

ashn% machne *./ * *.1 ( *.*1 *.1

Mcro4a+e o+en &( 2** / *.2 *.!

'"$"' or


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#xposure assessment studies so far have shown that most peoplePs #$%

exposure at wor< comes from electrical appliances and tools and from the

buildingPs power supply. "eople who wor< near transformers, electrical

closets, circuit boxes, or other high current electrical euipment may have

!*+-5 magnetic field exposures of hundreds of milligauss or more. 3n

offices, magnetic field levels are often similar to those found at home,

typically *. to .* mF. -owever, these levels can increase dramatically

near certain types of euipment =>.

The following figures 9%ig. 1*: are examples of magnetic field exposures

determined with exposure meters worn by four wor


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Fig. 1$ #agnetic $ield Exposures of 6orers 'm8(=>.

Table+2 may give a general idea about magnetic field levels for different

Dobs and around various


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)owadays, mobile telephony is commonly used all over the world. This

wireless technology relies upon an extensive networ< of fixed antennas,

or base stations, relaying information with radiofreuency 96%: signals.

Over 1. million base stations exist worldwide and the number is

increasing significantly with the introduction of third generation

technology =1*>.

$obile phone handsets and base stations present uite different exposure

situations. 6% exposure to a user of a mobile phone is far higher than to aperson living near a cellular base station. -owever, apart from infreuent

signals used to maintain lin


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ground. These antennas emit 6% beams that are typically very

narrow in the vertical direction but uite broad in the hori5ontal

direction. Aecause of the narrow vertical spread of the beam, the

6% field intensity at the ground directly below the antenna is low.

The 6% field intensity increases slightly as one moves away from

the base station and then decreases at greater distances from the

antenna =1*>.

Typically within 2+ meters of some antenna mounted on rooftops,

fences


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Chapter)

EM* IMPACT

ON EN.IRONMENT

"rotection of the environment and conservation of nature has become

matter of great interest to the public, as well as to governments. "ublic

concern about environmental exposure to #$% has ranged from claims of

reduced mil< production in cows gra5ing under power lines to damage to

trees near high power radars. Therefore, the 3mpact of #lectromagnetic on

environment was studied in numerous researches. review of the results

of such studies is summari5ed as followsJ

)"1 2uman ben%5

K#lectro+smogK is the bu55word which has directed public awareness

towards technical field emissions in recent years. ll over the world,

numerous studies have been carried out on the possible effects of

electromagnetic fields on humans, animals, plants and cell or tissue

cultures, and a series of large+scale epidemiological surveys has also been

conducted. The effects of electromagnetic fields generally depend on the

freuency and intensity, but also on individual characteristics such as

body si5e or angle towards the field =&>.

%indings have been largely substantiated with regard to the effects of

induced eddy currents at higher and medium+range field strengths 9%ig.

2


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11:, and these have formed the basis for the limit values in protective

legislation =&>.

Fig. 1$ %chematic &istri*ution of Edd! 9urrents :nduced *! #agnetic $ields

of 0ongitudinal and ransversal ;rientation owards the


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#lectromagnetic waves can be characteri5ed by their wavelength,

freuency, or energy. The three parameters are interrelated. #ach

influences the effect the field may have on a biological system.

The 3nternational #$% "roDect of 8-O is addressing the health concerns

raised about exposure to radiofre,!enc* (F)and microwave fields,

etremel* low fre,!enc* (/F)fields, and static electric and magnetic

fields. These electromagnetic fields can produce different biological

effects that may lead to health conseuences =11>.

adiofre,!enc* (F) fields"are .

6% fields at freuencies above about 1 $-5 primarily cause

heating by moving ions and water molecules through the medium

in which they exist. #ven very low levels of 6% energy produce a

small amount of heat, but this heat is carried away by the bodyCs

normal thermoregulatory processes without the person noticing it.

number of studies at these freuencies suggest that exposure to

6% fields too wea< to cause heating may have adverse health

conseuences, including cancer and memory loss. 3dentifying and

encouraging coordinated research into these open uestions is one

of the maDor obDectives of the 3nternational #$% "roDect.

6% fields at freuencies below about 1 $-5 primarily induce

electrical charges and currents which can stimulate cells in tissues

such as nerves and muscles. #lectrical currents already exist in the

body as a normal part of the chemical reactions involved in living.

3f 6% fields induce currents significantly exceeding this

2!


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bac


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and currents, other effects have been established to occur that could

potentially lead to adverse health conseuences, but only at very high

field strengths.

;tatic electric fields do not penetrate into the body, but can be

perceived by s.

;tatic magnetic fields have virtually the same strength inside the

body as outside. 0ery intense static magnetic fields can alter blood

flow or change normal nerve impulses. Aut such high field

strengths are not found in everyday life. -owever, there is

insufficient information about the effects of long+term exposure to

static magnetic fields at levels found in the wor


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;pecies, in particular certain fish, reptiles, mammals and migratory

birds, which rely on the natural 9geomagnetic: static magnetic field

as one of a number of parameters believed to be used for

orientation and navigational cues

%arm animals 9e.g. swine, sheep or cattle: gra5ing under power

lines 9*E!* -5: or in the vicinity of broadcasting antennas

%lying fauna, such as birds and insects that may pass through the

main beam of high power radio+freuency antennas and radar

beams or through high intensity #% fields near power lines.

;tudies performed to date have found little evidence of #$% effects on

fauna at levels below 34)36"Ps guideline levels. 3n particular, there were

no adverse effects found on cattle gra5ing below power lines. -owever, it

is


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)") A=uatc /fe

lthough all organisms are exposed to the geomagnetic field, marine

animals are also exposed to natural electric fields caused by sea currents

moving through the geomagnetic field. #lectro+sensitive fish, such as

shar


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Chapter#

STAN3AR3S

AN3 ,0I3E/INES

number of national and international organi5ations have formulated

guidelines establishing limits for occupational and residential #$%

exposure. The exposure limits for #$% fields developed by the

3nternational 4ommission on )on+3oni5ing 6adiation "rotection

934)36": + a non+governmental organi5ation formally recogni5ed by the

8orld -ealth Organi5ation 98-O:, were developed following reviews

of all the peer+reviewed scientific literature, including thermal and non+

thermal effects. The standards are based on evaluations of biological

effects that have been established to have health conseuences. The

main conclusion from the 8-O reviews is that #$% exposures below

the limits recommended in the 34)36" international guidelines do not

appear to have any


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Bespite of critici5ing of the 34)36" international guidelines as lacposure

lmts

*** 1** . ' 1*

(2


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;ome practical information will help to relate to the international

guideline values given above. 3n the following table 9Table :, the most

common sources of electromagnetic fields are listed. ll values are

maximum levels of public exposure =2>.

#able 5 !pical maximum pu*lic exposure

for the most common sources of electromagnetic fields[=].

Source Typcal ma>mum publc

e>posure

Electrc feld

:.?m7

Ma%netc flu>

densty :;T7

Mans po4er9in homes not close to

power lines:

1** *.2

Mans po4er

9beneath large power

lines:

1* *** 2*

Electrc trans and

trams(** *

T. and computer

screens

9at operator position:

1* *.&

Typcal ma>mum publc

e>posure :?m$7

T. and rado

transmtters*.1

Moble phone basestatons *.1

Radars *.2

Mcro4a+e o+ens *.

Bue to public anxiety in #gypt about mobile base stations, the )ational

Telecommunications 6egulatory uthority, )ational

((


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Telecommunications 3nstitute, $inistry of -ealth and "opulation, and

$inistry of ;tate for #nvironmental ffairs have thus Dointly produced a

modified manual of the reuired standards for installing mobile phone

base stations, up+to+date with the latest developments in

communications and information technology. This tripartite protocol

lists twelve conditions for the construction of cell sites as followJ

1. cell site must be constructed on a building that is 1 + * meters

high from surface, with the possibility of exceptions in case this is

not available.

2. The antenna must be higher than the other surrounding buildings

within a range of 1* meters.

(. The roof of the building on which the antenna is to be fixed must

be made of enhanced concrete.

. 3t is not permissible to fix more than one antenna on a single post.

. The distance between two cell sites must be at least 12 meters.

!. The distance between the antenna and the utmost reach of humans

must be at least ! meters.

&. ntennas may not be fixed on roofs that are not made of concrete.

/. ntennas may not be fixed on independent buildings, such as

hospitals.

'. ;ites must have a fence at a distance of ! meters from all

directions.

1*.4ompanies must adhere to the standards endorsed by the

merican 3nstitute for $easurements and the 3nstitute for the

#lectric and #lectronic #ngineers 93###:. The maximum

permissible power density a human being can be safely exposed

to must not exceed *. m8Ecm2 9'** $-S + 1/** $-S:.

11.ntennas may not be directed towards schools.

(


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12.%inally, pproval certifications that must be obtained are cited.

RE*ERENCES

1. 8-O, LElectromagnetic $ields and 1u*lic Health> the international E#$

pro?ect,M%act ;heet )o. 1/1, 8orld -ealth Organi5ation, $ay, 1''/.

2. 8-O, L6H; > %tandards and 8uidelines@Mavailable at

httpJEEwww.who.intEentityEpeh+emfEstandardsEenE

(. Aroo


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