E2science

Particle physicists know of the existence of three types (or "flavours") of neutrino: the electron neutrino, the muon neutrino, and the tau neutrino, each with their corresponding antineutrino. However, there is no reason why these should be the only neutrino types in the universe. One possibility for an unobserved neutrino flavour is the "sterile neutrino".

Neutrinos, being neutral leptons, can only interact via the weak nuclear force; they carry neither charge nor colour. Sterile neutrinos take this one further; they do not interact via the weak force either. This leaves them no avenue to interact through the standard particle physics forces, hence the name 'sterile'. A sterile neutrino can presumably interact via gravity, and it should participate in neutrino oscillation, where neutrinos spontaneously transform into different flavours as they propagate through space. The latter is more important, as it presents the only means of actually detecting a sterile neutrino. Many of the methods that have been used to determine the number of neutrino flavours are only sensitive to neutrinos that interact via the weak force, and thus are useless for detecting a sterile neutrino.

The rate of oscillation between two neutrino flavours is inversely related to the difference in mass between the two flavours. Since we have not yet seen neutrino oscillation into sterile neutrinos, we must conclude that any sterile neutrino must be very heavy, at least by neutrino standards. Present experimental limits require a heavy neutrino to be above 40 GeV in mass, or at least 40 times the mass of the proton. This contrasts with the wispy electron neutrino, which is known to be less than 3 eV, ten billion times smaller. The other two known neutrino flavours are believed to have comparable mass but have only been established to be less than the mass of the electron at 511,000 eV, still five orders of magnitude difference. Oscillation between such highly-disparate masses is only possible due to a high total energy.

In addition to the 'ordinary' sterile neutrino, which is identical to the known neutrinos outside of its mass and sterility, there is another class of neutrino that is effectively sterile, the 'wrong-handed' neutrino. One of the properties of the weak nuclear force is that it only couples to 'left-handed' particles and 'right-handed' antiparticles. (For more details, see the helicity and parity violation nodes.) Thus all interactions involving neutrinos only involve left-handed neutrinos and right-handed antineutrinos. This does not rule out the existence of right-handed neutrinos and left-handed antineutrinos, which may collectively be called 'wrong-handed', and, because of the weak force's selectivity in handedness, will be sterile.

The possibility of wrong-handed neutrinos is only tenable if the neutrino belongs to the class of particles known as Dirac particles. All known elementary fermions are thought to be Dirac particles, but since the neutrino has no electric charge, it is possible that it is instead a Majorana particle. Unlike Dirac particles, which have distinct antiparticles, a Majorana particle is identical to its antiparticle. If the neutrino is in fact a Majorana particle, then we call left-handed neutrinos 'particles' and right-handed neutrinos 'antiparticles' only because the weak force treats them differently, not because they are intrinsically different. This model does have some unusual features, particularly violation of lepton number conservation.

The ongoing search for sterile neutrinos is just one of the possible modifications of the Standard Model of particle physics presently being investigated by experiments. Although sterile neutrinos generally do not interact with other matter, they may be detectible through neutrino oscillations or by having very weak interactions with other particles, in particular, the property of the weak force that selects one particular handedness may not be absolute. At this point, the existence of a fourth, sterile neutrino flavour is considered unlikely, but the wrong-handed neutrinos are the subject of considerable ongoing speculation.

In a human society composed of over six billion individuals, it is impossible that any one person will know and befriend a significant portion of the rest of the people on Earth, yet with our newly developed global communication networks, it is possible that a significant portion of the rest of the world will have access to the information one person is sending or receiving. Because people generally mistrust, if not loathe, those whom they do not know, the person who is communicating, hereafter referred to as "Alicia," very often must keep her information secret from the faceless masses who could potentially be trying to listen in on the answering machine message she is leaving for her cat, Roberto, while she is on vacation. This is why we have developed data encryption, which can save us from the horrible embarrassment of having videos of us trying to emulate the light-saber fight from The Empire Strikes Back being distributed to our co-workers, or our plans for our newest biological warfare strain of smallpox being acquired by nations who do not embrace free-trade economics.

So, Alicia has to decide how to encrypt the data she want to send to Roberto. To do this, both Alicia and Roberto must have encryption keys. Alicia's key must encode the message, and Roberto's must decode the message. The standard methods of encryption used today usually use, at least in part, two different keys, Alicia's being a publicly available one, and Roberto's being a private (ultra top secret) decoder key. The secrecy of the transmitted message relies on the third party, Alicia's arch-nemesis Evita, being too stupid to solve the math involved in deriving the private key from the public one. This is all well and good, except that in this brave new world we live in, Evita may have a Commodore 64 or some other machine of unfathomable computational power, which could easily derive Roberto's private key. In fact, even if both keys were kept completely private, if Evita has by some insidious means acquired a some sort of super-intelligent robot, such as a 486, she could analyze multiple encrypted messages and derive the encryption algorithm. There is, however, a way to beat Evita's vast army of mechanical fiends. This method is known as the One Time Pad (OTP), and it has been theoretically proven to be completely secure and robot-proof.

The OTP method involves using only one key, that both Alicia and Bob, but absolutely no one else, know. They must use this key only once, which is fairly obvious considering this method's name. The key must be at least as long as the message Alicia wishes to send, and it must be generated completely and truly randomly (This means you can't generate an OTP using the Rand function on your Ti-83). This key is used both to encrypt and decrypt the transmitted message. For example, if Alicia wants to tell Bob 1001, and the randomly generated key is 0101, then Alicia could exclusive or (XOR) the message with the key and get 1100. This would be transmitted to Roberto, who would XOR 1100 with the key and get 1001, the original message. This is all well and good, except for the problem of how to generate a truly random and truly secret key that both parties know. Obviously Alicia could generate the key and then take it directly to Roberto, but then she might as well just hand him the message right there. This is where we can take advantage of the quantum mechanical properties of particles such as photons or electrons.

Quantum Cryptography is the single process of using the physical properties of quantum particles to both generate and transmit a secret one time pad. First I will describe the process, and then discuss the quantum mechanics. The most common method quantum key generation works by transmitting information via individual, polarized photons. To do this, we need four different possible polarizations for the photons which must comprise two sets of two orthogonal polarizations, such as Set A = (0, 90) degrees,and Set B = (-45, 45) degrees. We must designate bit values for each possible polarization. Both sets must have both a 0 and a 1. Let's say that 0 and -45 degrees correspond to 0, and that 90 and 45 degrees correspond to 1. The sender, presumably Alicia again, will send one photon at a time, the significance of which I will explain later, and she should randomly choose and then record the exact polarization of this photon by rotating the polarizer on her laser. When this photon reaches Roberto, he will randomly try to measure the photon in (Set A, 1) or (Set B, 1) by altering his polarizer between 90 and 45 degrees. If he measures that a photon passed through his polarizer, he records a 1, and if none passed, he records a 0. If he chooses the wrong set, then he will have a 50 % probability of measuring the photon, because 45 degrees is halfway in between 0 and 90 degrees. He will have this same probability no matter if Alicia's value was 0 or 1, as long as he is using the wrong set. However, if Roberto uses the right set, he will get the same bit value as the one Alicia has, because the photon will only pass through if Alicia used a bit value of 1. This means that when Alicia and Roberto's set value corresponds, their bit value must also correspond, no matter which particular bit value Alicia chose, and that when their set does not correspond, approximately half the bit values will also not correspond. Here is a logic table:

| Alicia's Polarization |  Roberto's Polarization  |	Roberto's Measurement	|
|-------------------------------------------------------------------------------|
|	A 0             |	   A 1             |	   0	                |
|	A 1             |	   A 1             |	   1	                |
|	B 0             |	   B 1             |	   0	                |
|       B 1             |	   B 1             |	   1	                |
|	A 0             |	   B 1             |	   0 or 1	        |
|	A 1             |	   B 1             |	   0 or 1	        |
|	B 0             |	   A 1             |	   0 or 1	        |
|	B 1             |	   A 1             |	   0 or 1	        |
--------------------------------------------------------------------------------

Therefore, after sending numerous photons in this manner, Alicia and Roberto can call each other up on a public phone line, and figure out for which photons they have the same Set recorded. They can then disregard all photons for which they used different sets, and without ever actually saying the bit values of the photons they agree upon, they know that the bit values must be the same in each of their records, because they agree upon the set. This set will then be used as a one time pad. They must also, however, tell each other the bit values for a small number of the photons they agreed upon, to make sure that the bit values are the same. If they are not the same, they know Evita was listening in. How? This is where the use of a single photon for each bit is key. If Evita intercepts the single photon, and measures it, she has to attempt to measure it with A1 or B1, just as Roberto would, but once she has done this, she has potentially altered the photon, thereby preventing her from transmitting the same photon back to Roberto. If she uses the wrong set, which she is 50% likely to do, then she alters the photon that she will then send on to Roberto, and she cannot know if she was using the right set until she eavesdrops on Roberto's and Alicia's conversation about which sets they used. Because the photon sent to Roberto was altered from the photon sent from Alicia, when they check to make sure they have corresponding bits, they will see that someone has been messing with their photons. If however, one were to attempt this type of key generation using a beam of multiple photons, Evita could simply divert two of the photons from the beam, and measure one with Set A and one with Set B. She could then let all the other photons go on their merry way to Roberto. Roberto and Alicia would not know anyone eavesdropped, and Evita would have a record of the bit value for every possible agreed upon photon. This would not do, so single photons must be used. Using this method, both Alicia and Roberto, who can be located far apart, have an identical copy of a completely secure random string of bits, which is the ideal one time pad encryption key.

When one tries to think of ways to eavesdrop effectively and undetectably on this system, the natural method that first comes to mind is to simulate a many-photon system. To do this, Evita would have to make identical copies of the photon sent by Alicia, and then proceed as she would if Alicia and Roberto were using flashlights instead of single photon lasers. However, this is impossible.

To be able to clone the exact state of a photon with an unknown state, would have all sorts of bad implications, including being able to go back in time. This can be shown with entangled particles. Quantum entanglement is the phenomena of two particles' quantum states being dependent on each other. The simplest example of quantum entanglement can be seen with particle spin, or angular momentum. If there is a large particle with zero angular momentum (no spin) , and it decays into two smaller particles with quantum spin, conservation of angular momentum tells us that that the spin s of the smaller particles must be in opposite directions of each other, in order to give a total zero angular momentum. The spin of either small particle is still randomly up or down, however, if we measure the spin of the first small particle and it turns out down, we know we have set the spin of the second small particle to up. A somewhat more complicated process can also produce photons with entangled polarizations. With entanglement of polarizations, two entangled photons are in the same polarization, though the specific polarization is undefined until measured.

To prove that there is no cloning, let us give Alicia and Roberto a set of entangled photons, and assume that Roberto has the superpower of quantum-state cloning. Let's also assume Roberto uses his powers to clone his entangled photon into a whole mess o' entangled photons. Alicia then runs her photon through a horizontal polarizer. Let's say the photon goes through the polarizer, so her photon is now horizontally polarized, which means all of Roberto's photon's are also horizontally polarized. Roberto measures half of his photons along a 45 degree polarization and half along a horizontal polarization. Those which he measures using the 45 degree polarizer will have a 50% chance of going through, but those he measures with the horizontal polarizer will have a 100% chance of passing. Therefore, if he uses his whole mess o' clones, he can see that Alicia has horizontally polarized her photon. The same process works when Alicia uses a 45 degree polarizer, so Roberto can determine instantaneously whether Alicia was using a slanted or a horizontal polarizer. This is transmitting instantaneously, which is, if Alicia and Roberto are in different positions, faster than the speed of light. This would mean that event A (Alicia's action) would influence an event in the past (Roberto's measurement). I could go into this further, but I'll just state that this shows that making a whole mess o' clones violates a whole mess o' established laws of physics. Therefore there is no cloning. Going back to where I started, this means that if Evita wants to know anything about that photon that Alicia sent, she's going to have to mess it up, and when Alica and Roberto are talking later, they're going to find out what's been going on, and they will know that the key they generated is bogus. That is why quantum key generation is completely secure.

However, the method I described is not entirely secure unless Alicia's choice of polarizations is truly random. Generating random numbers can be accomplished by measuring unknown photons, so in order to combine the two processes, many real quantum cryptography systems have a source of entangled photons in between Alicia and Roberto. Alicia and Roberto then both make measurements as Roberto did in my example, and the rest of the procedure is the same.

When I first heard about this method of generating a one time key. I thought that despite its unbelievable coolness, it must be almost completely theoretical, and that no one would have accomplished it outside of the unrealistic confines of a physics lab. It seemed to me, that generating a key would take a very long time. Alicia and Roberto have to throw out half their bits, prevent stray photons from interfering with their measurements, and generate an encryption key at least as long as the entire message they want to be encrypted. Doing this over any appreciable distance seemed nigh impossible, and I had strong doubts. But soft! What light through the National Institute of Standards and Technology's Colorado laboratory window breaks?* It is single photon laser light, traveling over 700 meters to the window of another laboratory for use in the fastest quantum key generation accomplished (As of May 2004). They transmit their photons through open air, preventing noise by turning their photon detector (Roberto) on only at the precise moment they expect a photon from the transmitter (Alicia). Amazingly, they have achieved rates of up to one million bits per second. Admittedly, compared to standard wireless communications that is not very good, but it is still very impressive. Furthermore, the Bank of Austria, in collaboration with the University of Vienna and several other organizations has successfully completed a quantum encrypted transaction just last month, and quantum encryption systems are beginning to go on the market, albeit for ridiculously high prices.

While this technology will not become commonplace anytime soon, and it is unlikely that it will ever become a household item, it is potentially very useful for large scale monetary transactions, spy agencies, top secret military communications, and especially ultra-paranoids, because lasers are definitely more fashionable than tin-foil hats.

Wikipedia ( "http://wikipedia.org/"): EPR paradox, Quantum Cryptography, Quantum Entanglement
Stanford Encycopedia of Philosophy ( "http://plato.stanford.edu/"): Quantum Entanglement and Infromation
NIST ( "http://www.nist.gov/public_affairs/releases/quantumkeys_background.htm"): Background on Quantum Key Distribution
TU Vienna QC ( "http://www.quantenkryptographie.at/"): Quantum Cryptography with Entangled Photons
Slashdot (slashdot.org)Search: Quantum Cryptography'
*I must admit that was a horrible joke, and it doesn't flow right at all, but I'm far too sleep deprived to remove it at this point

Carbon is known to most people as the lumps of black stuff that burn in fires. But if you think that this is its only form, you would be wrong! Carbon can be as white as elephants can be pink.

Carbon is a very flexible element - there are over sixteen million compounds of carbon, more than any other element. Because it has just the right size for fitting into the space between other molecules, it is capable of allotropes - commonly, diamonds and graphite, but more recently, a new allotrope, called white carbon or ceraphite, has been found.

White carbon was first made in 1969. It is unlikely to have existed naturally, as it has only been manufactured under extreme test conditions in a lab. It was produced at a high temperature (2550K, or 2277C) and low pressure, on the edges of graphite, another allotrope of carbon. Because of the change in conditions, the graphite sublimates and the white carbon forms as small crystals around it. These crystals can then be removed and examined. White carbon is transparent - it can be seen through - and birefringent - it has more than one index of refraction, which means it can split one ray of light into two separate rays.

Because so little is known about it, and it is very seldom-occurring, there are currently not many practical uses for white carbon. It has been reported to be extremely soft for a carbon product. In the future, however, more applications may be found: graphite is already a cheaper alternative to boron fibers, and white carbon, if it gets developed, may be a replacement for this. Confusingly, boron nitrite, which is used in sports equipment, is sometimes called 'white graphite'.

What follows is a series of brief reports about varying aspects of human interaction with the parasite Enterobius vermicularis.

Enterobiasis is a condition of helminth infestation affecting the intestinal tract. It is caused by the nematode Enterobius vermicularis, commonly known as the human pinworm (CDC, 2004). There are three main points of relevance concerning human interaction with this parasite: 1) The biology and characteristics of the pathogen, including the stages of the infection process, along with their corresponding symptoms. 2) How the pathogen is spread from one individual to another, as well as the role of the environment in facilitating or complicating transmission. 3) The diagnosis, treatment and prognosis of infected individuals. A solid grasp of each of these aspects is crucial in understanding the nature of the human pinworm and its relationship with human beings.

Compared to other microorganisms, pinworms are rather large. Adult females range in length from eight to thirteen millimeters. Males are notably smaller at two to five millimeters (CDC, 2004). Without regard to size, adult specimens look fairly similar in appearance to ordinary earthworms. The additional length of female specimens may be attributed to an anatomical structure that bares a striking resemblance to a lizard tail, extending to a point. This tail aids the in locomotion of females during their nightly migration to the perianal region to lay eggs which have been described as “colorless . . . smooth, thin eggshell[s] with one flattened side” (CDC, 2003, 2004). According to Lindsay (1997), Enterobius vermicularis has a direct life cycle, e.g. there is no intermediate host or vector involved. After the ingestion of eggs by the host, pinworms grow and develop in the large intestine where adult worms can live for 90 or more days (MMWR, 1993). While the infected individual is sleeping, the female worm uses its powerful tail to migrate through the intestinal tract to the rectum, where eggs containing larvae are deposited around the anus (MMWR 21, 1993). After only a few hours, these eggs may become infective, ready to reinfect the host, or spread to another individual.

While the presence of eggs may cause discomfort, primarily anal itching and general irritability, symptoms are generally mild or nonexistent (CDC, 1999). Additionally, pinworm eggs can survive independent of a host for up to two weeks, depending upon the nature of the surrounding environment (CDC, 1999; MMWR 21, 1993). The Centers for Disease Control and Prevention (2004) indicates that additional complications may occur in severe cases, including bacterial infection, due to unhygienic scratching of the perianal area, anorexia, caused by lack of appetite and vulvovaginitis, in the case that larvae “invade the female genital tract.” Vulvovaginitis is the inflamation of the vaginal mucosa in females. The mere presence of Enterobius vermicularis in the proximity of the vagina is often enough to trigger symptoms, however, bacterial infections can also easily result from agressive scratching.

While pinworm infestation is a worldwide pandemic, it holds the distinctive title of being the most common worm infection in the United States (CDC, 1999). For the most part, it affects young children and those living with or in close proximity to infected individuals. This is because young children are less likely to thouroughly wash their hands, and more likely to touch everything within their reach. Because of its mode of transmission, pinworm is commonly found circulating between children in preschool and grade school settings. Young children, in particular, are likely to be less reserved in their scratching, thus eggs may become caught beneath unwashed fingernails, in turn, contaminating anything they touch. The parasite is spread most commonly through accidental ingestion following contact with contaminated surfaces, such as clothing, bedding or fingers (CDC, 1999). Interestingly enough, the parasite may also be spread through the air by means of eggs attaching to dust particles, which may then be inhaled and ingested (MMWR, 1993).

If an individual’s symptoms suggest enterobiasis, a laboratory diagnosis may be used to verify the presence of infection (CDC, 1999). According to the Centers for Disease Control (2004), the laboratory diagnosis, must be performed first thing in the morning, prior to bowel movements or washing, and consists of the application of adhesive tape to the perianal region. The tape is then placed on a slide and examined under a microscope for the presence of eggs. Both bowel movements and washing have a high probability of removing the majority of eggs present in the anal region, potentially resulting in a falsely negative diagnosis. Alternative methods of diagnosis include the use of adhesive anal swabs which serve to collect any traces of eggs. Additionally, if adult worms are detected during an ano-rectal or vaginal examination, diagnosis is positive.

Generally, barring any bacterial complications, the prognosis for a full and quick recovery is good, i.e. there is no mortality. The drug mebendazole is used in a two-dose course to treat enterobiasis (CDC, 2004). Mebendazole works by systematically shutting down glucose uptake in the metabolism the worms, consequently leading to their death. Treatment with the drug has a success rate in the range of 90 to 95% (Infomed, 2005). Furthermore, taking the necessary steps to prevent reinfection is essential in the treatment of enterobiasis. These steps incorporate many of the rules of basic hygiene: bathe in the morning, change clothing and underwear daily, and wash hands frequently. Additional steps include trimming fingernails, and the avoidance of nail-biting and the scratching of bare anal areas, as the disease infects its hosts from hand to mouth (CDC, 1999). Furthermore, family members living in the same house as the infected individual should be treated with the same course of medication, to prevent further propagation of the disease. A follow-up test may be performed four weeks after the initial treatment begins, to make sure that no traces or eggs of the parasite remain (Infomed, 2005).

Enterobiasis is a mild but widespread disease that will not disappear any time soon (MMWR 9, 1993). While it rarely if ever seriously debilitates or kills an infected individual, pinworm is a nuisance that can cause severe discomfort prior to treatment. However, simply educating and convincing those at risk (school age children) to wash their hands frequently, especially before eating and after using the bathroom, could effectively reduce the number of annual cases.

Today, Enterobius vermicularis, or pinworm, is the most common intestinal parasite of humans in temperate climates with modern sanitation (Ashford, Hart and Williams, 1988). However, enterobiasis (pinworm infection) has likely affected human populations throughout the world for more than 10,000 years (Fry and Moore, 1969; Song, Cho, Kim and Choi, 2003). The parasite has such broad scope both historically and geographically, that it would be difficult to find a time in human history when pinworm was not present.

Written accounts of the disease throughout history, combined with archaeological data provide evidence for this lasting pandemic. Early medical writings verify the presence of human pinworm in China, India, the Middle East, and the Mediterranean. For example, Hippocrates (circa 460 BC–380 BC) was familiar with the clinical manifestations of the parasite, including the nightly migration of females to the perianal region to lay eggs, resulting in anal pruritus, irritation of the skin around the anus. These symptoms remain unchanged today (Fry and Moore, 1969; CDC, 2004). Coprolites positive for pinworm have been obtained through archaeological investigation at geographically distinct sites across North America and South America. The abundance of New World finds contrasts directly with a scarcity of Old World coprolite specimens positive for the parasite. Only three geographically distinct sites, located in Germany, China and Egypt, have yielded positive fecal samples in the Old World, although Horne (2002) suggests that this may be attributable to deficient inspection of coprolites from other Old World archaeological sites.

The finding of E. vermicularis eggs dating to 7837 BC ± 630 years in Danger Cave in western Utah marks the earliest recorded association of man with this “ubiquitous and exclusively human parasite” (Fry and Moore, 1969). Other specimens from nearby Hogup Cave date from around 4000 BC to as late as 600 BC, demonstrating that infestation was consistently present over a large span of time. Despite the fact that only 2.8 percent of coprolites from the caves contained pinworm eggs, the rate of infestation was probably much higher. Compared to modern studies of E. vermicularis employing the cellophane tape and swab technique to test for the presence of eggs, fecal examination shows less 5 percent of the actual infestation rate (Fry and Moore, 1969). Of the Old World coprolite specimens, the findings from the Dakhleh Oasis, in Egypt, are the oldest and most revealing, dating from 30 BC to AD 395. They represent the only known findings of E. vermicularis in ancient Africa (Horne, 2002). Thus, pinworm has had a presence on almost every continent, the notable exception being Antarctica.

While enterobiasis may affect human populations in nearly all climates, E. vermicularis is different from most other worms, it thrives in temperate regions (Juckett, 1995). According to Penner (1941), the viability of pinworm is reduced in environments where the temperature never falls below 62º Fahrenheit. This accounts for the lower rate of infestation in tropical and subtropical climes. While the parasite is spread mainly at the community and household levels, transmission of E. vermicularis also occurs between regions (global transmission) and between communities (regional transmission). The parasite could easily spread during travel or through trade. E. vermicularis eggs can survive independent of a host for up to two weeks, depending on the nature of the surrounding environment (CDC, 1993; CDC, 1999). Therefore, it is plausible to believe that the parasite could stow away on the surface of a package (ideally something that passes through many pairs of hands) in an aircraft or ship and spread to different areas. However, because of the high prevalence of E. vermicularis in nearly all temperate regions, travel and trade are not likely to affect the overall geographic distribution of the parasite. Within temperate regions, the parasite is endemic in nearly all communities. Which is to say, while E. vermicularis is spread between communities and regions, it doesn’t make a difference from a public health standpoint. In tropical regions, I suspect the parasite is more common in areas that are more or less developed and participate in frequent trade with countries in temperate regions.

At the community level, pinworm infection occurs more frequently in school-aged children (ages 5-14) than in the average population (Song, Cho, Kim and Choi, 2003). According to Rahman (1991), evidence suggests that the overall rate of infestation in the middle class residential community of Penang, Malaysia in 1991 was 30.6 percent (97 infected of 317 examined). The rate infestation for children ages 1-10 in the same community is 57.8 percent (37 infected of 64 examined; Figure 1).

Figure 1.  Presence of E. vermicularis eggs in Penang, Malaysia (Rahman, 1991)
	
        Age (years)	No. examined	No. positive
   
        1-10	        64	        37 (57.8 %)
	11-20		72		28 (38.9 %)
	21-30		78		12 (15.4 %)
	30-40		60		11 (18.3 %)
	> 40		43		9 (20.9 %)
	Total		317 		97 (30.6%)

Therefore, there is a definite correlation between the age of an individual and the prevalence of infestation, the greatest prevalence occurring in pre-adolescents. In urban and metropolitan areas, young children are more likely to be enrolled in preschools. These children are at a particular risk for enterobiasis, because of the ease of transmission in the preschool environment (Song, Cho, Kim and Choi, 2003). Young children are less likely to thoroughly wash their hands than older individuals when using the restroom. Moreover, young children are more likely to touch everything they can see and reach. This type of behavior and other juvenile habits such as nail biting and thumb sucking are significant factors facilitating the fecal-oral transmission of E. vermicularis. Juckett (1995) suggests that pinworm infections are often more severe in institutionalized patients than in the general population, however, he makes it clear that the parasite does not discriminate between people of different groups and socioeconomic levels. Furthermore, a study of risk factors for enterobiasis among preschool children in metropolitan Seoul in 2003 revealed that infection was more common in children ages 6-7 than in children ages 2-5. The researchers concluded that the older children had more opportunities for physical contact, facilitating the spread of the parasite (the younger children slept during recess). Additionally, infection rates were higher in preschools near traditional markets than those in residential areas, suggesting that sanitation and cleanliness also play important roles (Song, Cho, Kim and Choi, 2003).

Enterobiasis presents an interesting case at the household level. When one family member becomes infected, there is a high probability that all other family members will become infected. This high level of cross-infection is the result of an enormous number of eggs being produced in a short period of time, contaminating bedding, clothing and other surfaces around the home. Treatment is generally prescribed to the entire family, regardless of symptoms (Juckett, 1995). Reinfection is common within the household, thus rigorous cleaning is often recommended (Rahman, 1991). Again, enterobiasis is most common in schoolchildren, so one might expect that it would have greater prevalence in households with schoolchildren. Figure 1 shows that the parasite is least common in people between the ages of 21 and 30. Individuals within this age range are least likely to live in a household with children, and/or to have children of their own. Overcrowded living conditions may also contribute to a higher risk-factor for infestation (Song, Cho, Kim and Choi, 2003).

The relationship between humans in pinworms likely extends far into our past. Within communities and regions today, the public health issues surrounding enterobiasis are less related to the actual condition, and have more to do with the social stigma of having worms. Thus, widespread treatment is still worthwhile (Song, Cho, Kim and Choi, 2003). Although pinworm infection is mild, The Centers for Disease Control and Prevention (1993) maintains E. vermicularis is resilient, pervasive, and will not disappear any time soon.

Enterobiasis and the Hygiene Hypothesis

Enterobiasis has affected human populations for more than 10,000 years (Fry and Moore, 1969). However, in the last 50 years, infestation rates have dropped in industrialized countries. Around the middle of the 20th century, nearly half of Europe’s children were thought to be infested. Yet, recent data from Sweden suggests that infestation rates are now between 5% and 24% (Gale, 2002). These numbers reflect a broader trend of reduced helminth infestation among individuals in Western industrialized nations. On the other hand, rates of childhood asthma and childhood Type I (insulin-dependent) diabetes mellitus have risen risen in those nations(Gale, 2002). The hygiene hypothesis proposes that exposure to infectious agents (including Enterobius vermicularis) yields protection from developing those types of inflammatory diseases. Exposure to infectious agents is considerably reduced in Western industrialized nations when compared to developing nations, and this may explain the correlations between reduced helminth infestation rates and increased rates of allergic and autoimmune diseases in Western industrialized nations (Gale, 2002; Wilson and Maizels, 2004; Yazdanbakhsh and Matricardi, 2004).

While the exact role of parasites within the hygiene hypothesis remains controversial and is not fully understood, several studies have found a correlation between helminth infestation and inflammatory disease (Huang et al., 2002). In laboratory rodents, pinworm has been found to effectively inhibit the development of diabetes and other autoimmune diseases (Gale, 2002). According to Huang et al. (2002), there is also a negative association between enterobiasis and diseases such as asthma and rhinitis. They attribute this negative association to the protective effect of pinworm infestation against the development of inflammatory disease, though they do not rule out other possible mechanisms of association. In their study, 14.1% of individuals negative for pinworm infestation were diagnosed asthmatics, while only 9.3% of individuals positive for pinworm infestation had asthma. Additionally, 38.3% of individuals negative for pinworm infestation had been diagnosed with allergic rhinitis, but only 27.4% of individuals positive for pinworm infestation had received a diagnosis of allergic rhinitis.

As suggested in Wilson and Maizels (2004), cytokine modulation is central to the protective effect of parasite infestation against inflammatory disease. A cytokine is a protein responsible for “regulating the growth and activation of immune cells and mediating normal and pathologic inflammatory and immune responses”(Harrison’s Online, 2005). The cytokines responsible for dealing with immune responses to parasites include IL-10, as well as others. IL-10 is crucial in keeping the body’s immune responses under control and making sure that the presence of a parasite or other antigen does not provoke an overreaction. It is believed that helminths such as pinworm have the ability to stimulate production of regulatory cytokines like IL-10, ensuring that both host and parasite survive. These raised levels of IL-10 may also inhibit inflammatory responses to triggers such as allergens, protecting the individual from developing allergic and autoimmune diseases (Wilson and Maizels, 2004).

However, the mere presence of a parasitic infection does not guarantee a reduced likelihood of allergic and autoimmune diseases in an individual. The length of infestation must be prolonged enough for the body to adequately develop such a resistence. In populations where infestation is endemic and untreated, individuals are largely unaffected by allergic diseases. Helminth infestation in such areas may be characterized by either continuous infestation, or by a series of repeated episodes (Capron et al., 2004). However, even though Enterobius vermicularis is common throughout the industrialized world, it is often treated before any effective changes in the immune system can take place. According to Capron et al. (2004), the systematic eradication of helminth parasites in the West over the last 40 years, and the subsequent rise of allergic and autoimmune diseases, raises serious medical questions, particularly towards those scientists who have dedicated their lives to eliminating these parasites. Is it better to spend money treating a condition like enterobiasis, which is largely asymptomatic and harmless, thereby increasing the likelihood that rates of allergic and autoimmune disease will continue to rise, or to treat only those cases which are severe, in turn, decreasing rates of allergic and autoimmune disease? The diagnosis of parasitic infestation often carries a stigma, most people are not keen on the idea of a worm living inside them, but, there are points both for and against both sides of the issue.

The importance of this research lies in what it offers to immunologists. Understanding how the immunomodulatory properties of Enterobius vermicularis and other parasites influence the human immune response could be of great benefit to scientists developing treatments for immune-mediated diseases (Gale, 2002). Additionally, because it is the most common parasite in the industrialized West, a fuller understanding of the effects of Enterobius vermicularis on the human body would be a significant addition to the science of medicine.

In quantum mechanics no less than any other aspect of physics, the Simple Harmonic Oscillator is an extremely important system. In quantum mechanics, though, it leads to the 'zero-point energy', a common source of confusion among novices (and back when quantum mechanics was new, everyone was a novice).

The potential of the SHO is Aω²x²/2 + V, where V is the minimum of the potential, ω is the angular frequency associated with the oscillator, x is the parameter that's oscillating (position is a common case), and A is a constant. Note that though V is most often set to 0, this is merely a convention, and the value put here does not change any observable aspect of the system (this property is called Gauge Symmetry).

Just as with any other potential, the set of energy eigenstates (i.e. special states with precisely defined energy) of this potential spans the space of wavefunctions (i.e. states in general). That is to say, any conceivable state of the SHO can be expressed as a linear combination of states with definite known energies.

"So what?" you ask. Well, it turns out that the energy eigenvalues are

E_n = V + (n + 1/2)ℏω;

where ℏ is Dirac's constant, and each eigenvalue is labelled by n, and n is a nonnegative integer. This means that the minimum energy of the SHO is not the minimum of the potential, V, but V + ℏω/2. This is the zero-point energy.

What does this mean for energy extraction? Nothing. Ab-so-lute-ly nothing. You can't extract this energy, since there is no state with lower energy. Remember what I said about 'any conceivable state' up above. It does have a variety of implications for other things, principally that the mean kinetic energy and potential energy energies are nonzero; but that doesn't mean they can be gotten out without taking apart the oscillator¹.

Still, this freaked theoretical physicists out for quite a while, especially when it came time to quantize the electromagnetic field. You see, the electromagnetic field can be expressed as a sum of an infinite number of harmonic oscillators, one for each wavevector (read: frequency and direction). Having the ground state (one with no photons) have not only some energy but actually an infinite amount of energy really bothered them. Now, from a practical point of view, it made no difference, as energy in itself doesn't do anything², it's only differences in energy. The more pragmatic and less timid theoretical physicists simply chose the arbitrarily-set minimum of the potential, V, not to be 0 but rather be -ℏω/2. Thus, the total ground state energy was 0, and they could go with their business. Eventually, when their predictions ended up correct, the furor died down a bit.

As far as the public was concerned, though, the damage was done. The concept of 'zero-point energy', some energy that was at all points in space, just sitting there with no one using it, had leaked into the collective popular science consciousness. Ever since, we have received claims of 'harnessing the zero-point energy' from people who confuse Energy with Power, or think they've found a new solution of the SHO which has less energy than V + ℏω/2.

Recent experiments with attempts to find regions of negative energy (mentioned in the previous writeup) necessarily use the zero-point energy, but even in that interpretation, nowhere was the zero-point energy of the photon field extracted; merely it was observed to have an effect.

Also note that any bound state has a zero-point energy, but the SHO of the photon field is the one that gets most of the attention. Why? For most other bound states, V is selected so that it is 0 at all points infinitely far away from the points of interest. If the state is truly bound, that means that the energy of the system is less than V at infinity: 0. For example, the zero-point energy of the hydrogen atom is -13.6 eV. A negative zero-point energy is unexciting to the average person, but it's basically the same. The only reason this isn't done for the SHO is because the potential diverges at infinity, so that convention is impossible.

Related to Zero-Point Energy is the notion that one can extract huge amounts of energy from water. This isn't the same thing exactly, but it does arises from the same problem - thinking that there's a lower-energy state that all the water on Earth keeps on not finding its way into, for no particular reason. Suffice it to say, the oceans are not critically unstable high explosives.

¹ this caveat is important. You can extract the ZPE of an oscillator which you made yourself, by relaxing the oscillator in such a fashion as to absorb the energy. But this is just recovering energy you had to put in to make the oscillator in the first place...

² except in General Relativity. This was one of the more serious problems, except in that we could readily measure that there was a non-infinite energy density at every point in space. In this sense, the 'convenience' solution became a necessity.