Nooriye is a 39-year-old Iraqi female. She had a pretty normal life until a group of terrorists knocked on her door. Her two sons were killed in front of her. She was abused and tortured for days, as was her husband. Rebels eventually took her husband and left. Some neighbors helped her to bury her sons and provided her with shelter and food. She was about to kill herself when, miraculously, her husband came back 57 days later. He never told her what he went through during those 57 days. They were both in extreme pain but able to hold onto each other.

They immigrated to the U.S. a year later. Her husband found a job and is still working. They are safe now, but it has not been enough to heal them. Both still have nightmares and flashbacks. She spends all her time in her home. She stares at walls, feels numb and very fearful, and cries every day. Her speech is sparse, and she never smiles. She goes out with husband once a day but grabs his hand and won’t let him go when they are out. When faced with stress, she often passes out.

Her husband “has to be strong because she is the only thing he has,” although he also has extreme pain. He hides his tears from his wife, is unable to sleep at night, feels guilty, and misses his sons. He is afraid to make any Iraqi friends and stays away from mosques.

Obviously, providing a safe place, food, and a job is not enough to heal these people’s pain. Invisible wounds and problems are much harder to treat than visible ones.

In this article we will try to elucidate some elements of what Nooriye and thousands of other families have been exposed to all around the world.

Mass trauma

When a group of people, regardless of size, experience psychological effects after a trauma that was suffered collectively, this is called a mass trauma. Sometimes an entire society witnesses the same trauma, and this may cause a collective sentiment, often resulting in a shift in that society’s culture and mass actions.^1,2

Wars, political violence, natural disasters, exile, torture, and terrorism are examples of mass trauma. The Holocaust, the Atomic bombing of Hiroshima and Nagasaki, slavery in the United States, and the 9/11 attacks are well-known collective traumas.

Collective traumas have been shown to play a key role in group identity formation. Having the same problems, suffering from the same pain, and being under the same pressures bring individuals together. This togetherness eventually helps to build a community, a group, and sometimes a nation. Almost every nation has traumatic events in their history. Even the concept of “nation” is extensively affected by these events.

Nevertheless, despite its role in building group identity, mass trauma is still individually painful. In fact, the effects of mass trauma can be very deep and transferred through the generations. In 1966, clinicians observed that large numbers of children of Holocaust survivors were seeking treatment in psychiatric clinics in Canada. Moreover, when compared to the general population, the grandchildren of Holocaust survivors were three times more likely to seek clinical psychiatric help.³

Post-Traumatic Stress Disorder

According to the National Center for Posttraumatic Stress Disorder, the most common stress reactions in the wake of disaster may include the following:

Emotional reactions, including shock, fear, grief, anger, guilt, shame, feeling helpless, feeling numb, and sadness.

Cognitive reactions, including confusion, indecisiveness, worrying, shortened attention span, and trouble concentrating.

Physical reactions, including tension, fatigue, edginess, insomnia, bodily aches and pains, startling easily, racing heartbeat, nausea, change in appetite, and changes in other bodily desires.

Interpersonal reactions, including distrust, conflict, withdrawal, work or school problems, irritability, loss of intimacy, and feeling rejected or abandoned.⁴

Several factors present in the acute-phase recovery environment of a disaster have been found to aggravate stress reactions and therefore increase survivors’ risk of developing negative outcomes. These include:

• Lack of emotional and social support
• Presence of other stressors such as fatigue, cold, hunger, fear, uncertainty, loss, dislocation, and other psychologically stressful experiences
• Difficulties at the scene
• Lack of information about the nature and reasons for the event
• Lack of, or interference with, self-determination and self-management
• Treatment [given] in an authoritarian or impersonal manner
• Lack of follow-up support in the weeks following the exposure

Protective factors that may mitigate negative effects include:

• Social support
• Higher income and education
• Successful mastery of past disasters and traumatic events
• Limitation or reduction of exposure to any of the aggravating factors listed above
• Provision of information about expectations and availability of recovery services
• Care, concern and understanding on the part of the recovery services personnel
• Provision of regular and appropriate information concerning the emergency and reasons for action.⁵

In most cases, the symptoms of trauma eventually disappear, but unfortunately, some of the survivors of the mass trauma will eventually develop Post-Traumatic Stress Disorder (PTSD). PTSD is a mental disorder resulting from exposure to an extreme traumatic stressor.

The National Comorbidity Survey Replication (NCS-R), conducted between February 2001 and April 2003 in the U.S., estimated the lifetime prevalence of PTSD among adult Americans to be 6.8%.⁶ The lifetime prevalence of PTSD among men was found to be 3.6% and among women 9.7%. ⁷

PTSD is described in the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) (DSM 5) which is published by the American Psychiatric Association, as:

Criterion A (at least one required): The person was exposed to: death, threatened death, actual or threatened serious injury, or actual or threatened sexual violence, in the following way(s):

• Direct exposure
• Witnessing the trauma
• Learning that a relative or close friend was exposed to a trauma
• Indirect exposure to aversive details of the trauma, usually in the course of professional duties (e.g., first responders, medics)

Criterion B (at least one required): The traumatic event is persistently re-experienced, in the following way(s):

• Intrusive thoughts
• Nightmares
• Flashbacks
• Emotional distress after exposure to traumatic reminders
• Physical reactivity after exposure to traumatic reminders

Criterion C (at least one required): Avoidance of trauma-related stimuli after the trauma, in the following way(s):

• Trauma-related thoughts or feelings
• Trauma-related reminders

Criterion D (at least two required): Negative thoughts or feelings that began or worsened after the trauma, in the following way(s):

• Inability to recall key features of the trauma
• Overly negative thoughts and assumptions about oneself or the world
• Exaggerated blame of self or others for causing the trauma
• Negative affect
• Decreased interest in activities
• Feeling isolated
• Difficulty experiencing positive affect

Criterion E (two required): Trauma-related arousal and reactivity that began or worsened after the trauma, in the following way(s):

• Irritability or aggression
• Risky or destructive behavior
• Hypervigilance
• Heightened startle reaction
• Difficulty concentrating
• Difficulty sleeping

Criterion F (required): Symptoms last for more than 1 month.

Criterion G (required): Symptoms create distress or functional impairment (e.g., social, occupational).

Criterion H (required): Symptoms are not due to medication, substance use, or other illness.⁸

Treatment for mass trauma:

Treatment for mass trauma should be delivered at two different levels: the community level and the individual level.

1. Community level:

Dr. Frantz Omar Fanon gives the recipe for mass trauma treatment at the community level: “Mass trauma can be alleviated through cohesive and collective efforts such as recognition, remembrance, solidarity, communal therapy and massive cooperation.”

The statement above can be a topic for a separate article. Here, we would like to express the importance of the remembrance days. People comes together on remembrance days and remind the victims that they are not alone and not forgotten. This can be therapeutic for the victims and alleviate their pain.

2. Individual level

PTSD treatment includes pharmacotherapy (medical treatment) and psychotherapy. Some of the medications which have been helpful combatting depression are selective serotonin reuptake inhibitors (SSRIs), such as Fluoxetine (Prozac), Sertraline (Zoloft), Paroxetine (Paxil), and serotonin-norepinephrine reuptake inhibitors (SNRIs) such as Venlafaxine (Effexor) and Duloxetine (Cymbalta).

There are several therapy types that have been shown to be effective at treating PTSD. Trauma-focused psychotherapies are the most highly recommended psychotherapies for PTSD. In these therapy types the treatment focuses on the memory of the traumatic event or its meaning. These treatments use different techniques to help a victim process their traumatic experience. Some involve visualizing, talking, or thinking about the traumatic memory. Others focus on changing unhelpful beliefs about the trauma. Prolonged exposure therapy, Cognitive Processing Therapy, Eye-Movement Desensitization and Reprocessing, Brief Eclectic Psychotherapy, and Narrative Exposure Therapy are the some of the therapies that have been found to be helpful for PTSD patients.

Additionally, spirituality might help treat PTSD, too. A study of Bosnia-Herzegovina war veterans suggested that veterans who prayed had significantly higher levels of incorporation, self-protection, and reactive formation and significantly lower levels of regression, compensation, transferring, lack of control, and aggressiveness than their peers who did not pray. ⁹

In brief, providing shelter, food, and a safe environment are mandatory for trauma patients, but they aren’t nearly enough. Psychological traumas are very hard to treat, and treatment may take years. It has been shown that soldiers who have somebody to share their war experience/trauma with, have a lower risk for PTSD when compared with the ones who can’t talk to anybody. Victims need professional help along with community support. Trauma can be alleviated through cohesive and collective efforts and cooperation. Praying for the trauma victims, as politicians suggested for recent hurricane victims, definitely has some social impact. It has also been shown that medication/prayers decrease PTSD symptoms ¹⁰; however, showing support and empathy, listening to victims, and acts of remembrance are the other key elements of community support.

References

1. Lisa Gale Garrigues, “Slave and Slave Holders Break Free of History’s Trauma“, Yes Magazine, August 2, 2013
2. Updegraff, Silvler, Holman, “Searching for and Finding Meaning in Collective Trauma, Journal of Personal and Social Psychology, September 2008
3. Coffey, R. (1998). Unspeakable truths and happy endings. Sidran Press. ISBN1-886968-05-5
4. https://www.ptsd.va.gov/professional/pages/handouts-pdf/Reactions.pdf
5. NSW Institute of Psychiatry and Centre for Mental Health. (2000). Disaster Mental Health Response Handbook.North Sydney: NSW Health.
6. Kessler, R.C., Berglund, P., Delmer, O., Jin, R., Merikangas, K.R., & Walters, E.E. (2005). Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Comorbidity Survey Replication. Archives of General Psychiatry, 62(6): 593-602.
7. National Comorbidity Survey. (2005). NCS-R appendix tables: Table 1. Lifetime prevalence of DSM-IV/WMH-CIDI disorders by sex and cohort. Table 2. Twelve-month prevalence of DSM-IV/WMH-CIDI disorders by sex and cohort. Accessed at: http://www.hcp.med.harvard.edu/ncs/publications.php
8. American Psychiatric Association. (2013) Diagnostic and statistical manual of mental disorders, (5th ed.). Washington, DC.
9. Pajević I, Sinanović O, Hasanović M. Association of Islamic Prayer with Psychological Stability in Bosnian War Veterans. J Relig Health. 2017 Dec;56(6):2317-2329. doi: 10.1007/s10943-017-0431-z.
10. Gallegos AM, Crean HF, Pigeon WR, Heffner KL. Meditationand yoga for posttraumatic stress disorder: A meta-analytic review of randomized controlled trials. Clin Psychol Rev. 2017 Dec; 58:115-124. doi: 10.1016/j.cpr.2017.10.004.

Original article: Olzsak T. et al, Science (2012, epub ahead of print)

It has been known by epidemiologists that people who grew up in farms are less likely to acquire immune diseases such as asthma, allergies, inflammatory bowel disease and multiple sclerosis when compared to people living in cities. Such observations have been the roots of “hygiene hypothesis,” which essentially points out the beneficial effects of being exposed to infectious agents. Supporting this theory, a recent study at Harvard Medical School showed that exposure to symbiotic bacteria has a long lasting beneficial effect on the immune system development. “We as a species are not exposed to the same germs that we were exposed to in the past,” said the co-author Dennis Kasper, a microbiologist at Harvard Medical School in Boston. In this study, published in Science, the researchers compared germ-free mice to mice with normal bacterial flora. Germ-free mice showed significantly higher levels of invariant natural killer T (iNKT) cells in their colons and lungs. “We made the serendipitous observation that these cells were dramatically enriched in the lung and colon in mice that lacked any microbes,” said the co-author Richard Blumberg, the chief of gastroenterology at Brigham and Woman’s Hospital in Boston. Body’s own production of elevated iNKT cells correlated with higher susceptibility to inflammatory bowel disease and allergic asthma in germ-free mice. Most strikingly, the study showed that exposure to these bacteria in late age did not lower the susceptibility to these immune diseases, indicating that the bacterial exposure needs to be early in life to boost the immune system. After all, broad-spectrum antibiotics for babies may not be such a good idea.

2- Giant chickens of Jurassic Park

Original article: Xu X. et al, Nature 484, 92 (2012)

Many of us undoubtedly learned a lot about dinosaurs from the famous Sci-fi movie Jurassic Park, but who would have imagined that some gigantic feathered dinosaurs would be running along with our favorite monster T-Rex? Paleontologists have recently made an incredible discovery in Liaoning Province of China. They found a set of perfectly preserved fossils that belong to a previously unknown species of dinosaurs. These 125-million-year-old feathered giant dinosaurs represent the largest feathered animal species ever lived on earth. The adult one is predicted to be at least 9 meters (30 feet) long with a weight of 1400 kg (~3000 pounds), which is approximately 40 times bigger than the Beipiaosaurus, largest known feathered dinosaur. New gigantic feathered dinosaurs are given a Chinese-Latin name Yutyrannus huali meaning a “beautiful feathered tyrant.” Simple filament like structures as well as the relatively small sizes of feathers seem more similar to feathers from a baby chick than the plumes of an adult bird, suggesting that Yutyrannus used feathers not for flying but for body temperature insulation, perhaps under the harsh climate conditions of that age. Paleontologists are really excited to see that how much more we have learned about dinosaurs over last 15 years and they predict that many different feathered meat-eating dinosaurs lived before and they are still yet to be discovered.

3- Stardust mystery revealed

Original article: Norris B.R.M. et al, Nature 484, 220 (2012)

Heavy elements are formed in the cores of stars and are crucial in formation of celestial structures like our earth. When an intermediate-mass star dies, it triggers a cosmic sandstorm that lasts thousands of years ejecting more than half of its mass into space. Our Sun is expected to go into a similar phase in around 5 billion years. Scientists observed these sandstorms for years but it was a mystery how these particles found could leave the vicinity of the stars and find their way into interstellar space. Computer simulations hinted that these sand-like particles could not be that small, otherwise they would be evaporated by the immense heat of the dying star. Scientists using the Very Large Telescope in Chile had a chance to explore these stars in a greater detail and discovered that the size of these particles is around a micrometer. This size might seem very small to us but for these particles, it is large enough to behave like mirrors for the light rays coming out of the star instead of absorbing them. Since light also behaves like a particle, the momentum transferred by this reflection helps particles to accelerate to the speeds like 10km/second. As the lead author of the study, Barnaby Norris from University of Sydney says: “The dust grains are like lots of little sails catching the wind, or in this case, starlight.” The material that comes out of the stars is recycled during the formation of new stellar objects like our old planet.

4- Babies understand more than we think

Original article: Bergelsona, E. & Swingley, D., P.N.A.S. 109, 3252 (2012)

Most babies do not say a meaningful word until they are a year old. It was not clear whether they knew the meaning of the words prior to the speaking age. It is easy to ask the question on whether the babies understand words but it is hard to scientifically measure it. The researchers from the University of Pennsylvania devised an ingenious experiment to test the hypothesis whether the 6-9 months babies understood the common words. During the experiment babies sat on their parents’ lap in front of a computer while some images of body parts or foods were shown on the screen. The parents were given instructions through headphones about what to say to the baby about the image on the screen. Babies were monitored by an eye-tracking device to measure their attention being directed to screen. The researchers designed a control environment by pairing a body part and a food item. For instance, if a banana and some hair were shown on the screen, the researchers measured the time that the baby fixated on the banana when the parent instructed the child to look at the banana versus when the parent instructed the baby to look at the hair. 33 infants of ages 6 to 9 months and 50 toddlers of ages 10 to 20 months were recruited for this study. The study convincingly showed that the babies fixated longer on an object when they were instructed to do so. Moreover, as the age of the babies increased the period of fixation stayed pretty much constant until 14 months, but jumped dramatically afterwards. The reason behind the jump in 14 months begs further research. Now, the researchers want also to test the vocabulary of the babies and whether the babies also understand the abstract concepts.

Original Article: Mak, G.K. & Weiss, S., Nature Neuroscience 13, 753 (2010).

Motherhood or maternal recognition is well characterized by associated brain plasticity during both early development and adulthood. Unlike motherhood, paternal-offspring recognition and its related brain plasticity is poorly understood. A group from University of Calgary designed a set of experiments to test whether father mice can recognize their own infants once they’ve reached adulthood. They exposed adult males to their own and genetically unrelated infants for 2 days. The fathers were tested for adult offspring recognition six weeks later. Assay compared the time spent by the fathers with their own and unrelated offsprings. Results showed that although the father mice show similar parenting behavior toward both sets of infants (own and adopted), they only recognize their own pups as adults. Paternal recognition is associated with increased prolactin (a hormone primarily associated to lactation), mediated neurogenesis in the olfactory bulb, and hippocampus, a major component of mammalian brain. These newly generated neurons are important for the formation of socially relevant olfactory memories. Authors also found that the fathers must physically interact with the infants in order to recognize them later. This is confirmed by some control experiments in which fathers are only allowed to see, smell or hear infants through a wire mesh barrier which was not sufficient to induce neurogenesis. One of the socially relevant benefits of paternal recognition of the infants as adults is to avoid incest interactions which cause inbreeding depression.

2- Recently revealed hideous effects of smoking on children

Original Articles: Brion, M.J. et al., Pediatrics 126, e57 (2010) & Kwok, M.K. et al., Pediatrics 126, e46 (2010).

Smoking is bad for our health, but apparently it may also have subtle, yet far-reaching consequences on our children according to two recent studies. The first study reports that mothers who smoke during pregnancy are more likely to have children with psychological problems. A related study presents evidence that babies who develop in the presence of second-hand smoke (from their fathers) may develop weight problems. Dr. Mary-Jo Brion of the University of Bristol tells “Babies exposed to smoke (in the womb) may be prone to rule breaking, such as lying, cheating, bullying, and disobedience in later years” and adds “To some extent it is somewhat surprising that … maternal smoking may also directly impact child behaviors from exposing the fetus to tobacco in utero.” The other study suggests that smoking around expecting mothers (even when the mother herself is not smoking) also affects the child: higher childhood weight appears to be clearly correlated with paternal smoking. “To protect their children, fathers should avoid smoking from conception onward,” says Dr. Mary Schooling of the University of Hong Kong. Furthermore, smoking mothers should not be too surprised to see their children “disobey” when they tell them not to smoke.

3- Exposure to certain wavelengths of light resets the body clock

Original Article: Gooley, J.J. et al., Science Translational Medicine 2, 31ra33 (2010).

With the introduction of high-tech gadgets into our lives, our daily functions have changed drastically. As opposed to old-fashioned bed-time reading of an “actual” book made of paper, we fiddle with our iphones or ipads or notebooks or channel surf on our bedside TVs before going to sleep. A recent study revealed that exposure to certain wavelengths of light, such as those from laptops or TVs, would negatively influence our circadian rhythms (daily rhythmic activity cycle) by resetting our body clocks (e.g., keeping us awake when we should be sleeping). The feeling of sleepiness at night time is triggered by the secretion of a hormone called melatonin. It had been known that exposure of blue light to the eye’s photoreceptor system located in the ganglion cells suppresses the melatonin secretion, therefore stimulating alertness. In their recent work, researchers at Brigham and Women’s Hospital showed that green light exposure of a different cell population on the eyes – cone cells – also resets the body clock by suppressing melatonin secretion. The senior author of the paper, Dr. Steven Lockley, said in an interview that “we need to think about the entire spectrum of light when designing light therapy or lightning designs to boost alertness or induce sleepiness.” The moral of the story is to be more vigilant about our interaction with fancy electronic gadgets at night if we want to have a healthy and relaxing sleep.

4- Poor teachers may impede good students

Original Articles: Taylor, J. et al., Science 328, 512 (2010).

Scholars know that educational environment, including both tasks and the social environment of a classroom, affects children’s achievement just as much as genetic factors. But the teacher plays a main role, because the quality of the educational environment depends on teachers’ performances. A new study underlined the importance of qualified teachers and how they can make a difference in education. The researchers examined the influence of teacher quality by studying 280 identical and 526 fraternal twin pairs in the first and second grades in different Florida schools representing a diverse environment. Identical twins share 100 percent of their genes and fraternal twins share half, and some of the twins were taught by the same teacher but some were in different classes. The researchers used an Oral Reading Fluency test which is based on how many words in a paragraph a child can accurately read in a minute in order to assess the reading skills of children. The researchers recorded the reading scores of students in the beginning of the semester and at the end of the semester, and they followed the students’ improvements during the year. To measure teacher quality, they used the scores of twins’ classmates. By studying twins’ groups, researchers were able to eliminate some other factors such as genetics and socio-economic conditions. According to the findings, the teachers played a role in “moderating” students’ achievements, and they helped the students to grow to their full potential. When teacher quality is very low, genetic variance is constricted, whereas, when teacher quality is very high, genetic variance blooms. As the study’s lead author, Jeanette Taylor, said “Better teachers provide an environment that allows children to reach their potential.”

In today’s cellular communication systems, cellular phones operate in several frequency bands. European systems use the Global System for Mobile Communications (GSM) at around 900 MHz and 1800 MHz; American systems use 850 MHz and 1900 MHz, frequencies that fall between the operating frequency ranges of televisions and microwaves. This frequency range is called non-ionizing, for the wave’s energy does not release electrons from atoms in living tissue. For instance, an X-ray is an ionizing wave that, to a degree, damages exposed biological material. Therefore, most concerns deal with RF energy’s heating effect rather than with ionization.

Technical Motivation

The electromagnetic spectrum extends from DC (direct current) to ionizing radiation. Scientists divide this spectrum into subregions. Cellular phones fall into the ultra-high frequency (UHF) regime, specifically from 300 MHz to 3000 MHz. By itself, a continuous UHF wave carries no information and does not enhance communication. It only becomes useful when modulation, defined as means carrying the information on a high frequency carrier, like UHF, is applied. The most common modulation techniques are amplitude modulation (AM) and frequency modulation (FM).

The capacity of the spectrum’s given section to carry information is limited by the Shannon Theorem. According to this theorem, channel capacity can be increased by increasing the system’s signal-to-noise ratio. In wired communications, channel capacity can be increased by adding more parallel optical fibers. Channel capacity in wireless communications can be increased by transmitting weak signals that attenuate rapidly near the transmitter and thus provide a given portion of the electromagnetic spectrum to be utilized many times. How a given spectrum is allocated among users affects the channel capacity. Therefore, there are several coding techniques, the most common of which are Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), and Code Division Multiple Access (CDMA).

Neglecting some small details, an electromagnetic (EM) wave’s energy is expressed in terms of power density (W/m2) across a surface. Power density measures an incident EM wave’s strength. Easily measured, it is a very preferable metric to UHF fields. For uncontrolled environments, the American National Standards Institute and the Institute of Electrical and Electronics Engineers (ANSI/IEEE C95.1) recommend a 2 to 20 W/m2 for an average external exposure to UHF. The International Commission on Non-Ionizing Radiation Protection (ICNIRP) has similar power density recommendations for limiting the general public’s exposure to RF energy so that people will not be overheated by RF energy. As a comparison, for example, summer sunshine peaks around 1000 W/m2.

However, as power density is not a good indicator inside a living organism, scientists have defined a Specific Absorption Rate: SAR (in W/kg). For uncontrolled environments, ANSI/IEEE limits the spatial-average SAR to 0.08 W/kg whole body and to 1.6 W/kg averaged over any 1 gram of tissue. Also, 1998 ICNIRP restrictions are similar to ANSI/IEEE’s. The SAR can be estimated in three ways.

– Micro-antenna: Small antennas can determine a tissue’s electric field as well as its SAR. But it is difficult to place the antenna, and the tissue’s properties may not be known.

– Miniature thermal probes: Since RF energy heats the tissue, this technique detects the heat and the SAR in the neighborhood of the temperature cell, which then can be computed accordingly. However, this method also seems very difficult technologically.

– Numerical modeling: The numerical modeling of macroscopic bodies enables a numerical simulation, known as the Finite Difference Time Domain (FDTD), that can estimate the SAR. However, this process can be time-consuming and expensive.

Possible Health Issues

An EM wave can effect a biological change in living tissue in two ways: Depositing enough energy while passing through the biological material to alter some structures, or depositing packets of energy larger than the bond energy. Yet neither way seems to be possible, for the photon energy within the UHF zone is far less than the bond energy or the energy required to alter a living tissue’s structures. Therefore, many scientists now argue that UHF radiation at subthermal power levels can cause some biological damage.

Due to relatively low exposure levels, relatively small populations, and a lack of reliable dose estimates, proving or disproving the existence of RF exposure’s biological hazards remains an issue for epidemiology (e.g., statistical analysis of health records and animal studies).

Epidemiological Studies

Epidemiological studies were conducted among people who worked in a high frequency environment, such as radar stations. Search criteria were not limited to cellular and personnel communication system (PCS) frequencies. Due to the nature of radar and other military equipment, broader frequency ranges were covered. The epidemiology of cancer and RF radiation includes studies of cancer mortality rates among those exposed to RF energy.

Throughout these studies, people’s records were searched to determine if their cancer was due to RF exposure. These studies were made in various institutions, including the Radar Laboratory of the Massachusetts Institute of Technology, the U.S. Navy and Air Force, and the Polish military. There was no conclusive evidence that RF exposure increases the risk of cancer. Also, due to the lack of comparisons with total cancer, it was suggested that RF exposure does not have a strong effect on cancer.

Since brain cancer takes a long time to develop and epidemiological studies tell nothing about future risks, these studies have not proved or disproved that RF exposure increases the risk of cancer.

Animal Studies

Animals are the other source of information that potentially may answer people’s concerns. Experiments have studied rats exposed to certain power levels of RF energy. However, these studies found no link between cell phones and cancer.

In 1999, a Motorola-funded research program concluded that exposing rats to pulse-modulated 837 MHz RF energy, very close to that radiated by a digital cell phone, does not cause or develop brain cancer. A study in April 2000 reported that this conclusion is valid for continuous-wave RF (analog cell phones). But a 1995 study at the University of Washington (Seattle) reported that exposing rats to RF radiation at an average whole-body exposure of 1 W/kg of body weight caused breaks in their brain cells’ DNA, which is an indication of cancer. No other study has confirmed this finding.

Other studies have focused on different aspects of RF radiation rather than brain cancer. They searched animals for certain diseases and noticed an increase in disease rate. However, despite such research findings, animal studies seem to be far removed from human health.

Conclusion

Epidemiological findings and animal studies have neither proved nor disproved the health hazards of mobile phones. A February 2000 essay by the U.S. Food and Drug Administration (FDA) stated that: There is currently insufficient scientific basis for concluding either that wireless communication technologies are safe or that they pose a health risk to millions of users. Research activity continues. For example, France’s International Agency for Research on Cancer has received a research project of 8 million euros from the European Commission for a 3-year, wide epidemiological study. Also, the FDA and the Cellular Telephone Industry Association have undertaken a $1 million research project to clarify the health risks of mobile phones.

Meanwhile, some researchers are trying to find the head’s SAR by using electromagnetic simulations (FDTD). So far, they have discovered that it is strongly affected by the cell phone’s position as well as the head’s shape and properties. Therefore phone-makers are trying to design handset designs to reduce the SAR. However, it seems that the debate will remain until scientific proof is confirmed and made available.

• References
• http://www.fda.gov/cdrh/ocd/mobilphone.html.
• IEEE Spectrum. Are Mobile Phones Safe? (August 2000): 23-28.
• Moulder et. al. Cell Phones and Cancer: What is the Evidence for a Connection? Radiation Research Society, 151 (1999): 513-31.