Eliminating smallpox was probably the greatest global health victory of the last century, if not ever. It was made possible by remarkable cooperation between the United States and the Soviet Union of a sort which was rare in the Cold War. And it also, bizarrely enough, owed a lot to the Vietnam War.

The smallpox drive was carried out under the auspices of the World Health Organization, which was largely funded by the United States. The Soviets had refused to participate in the organization after 1948, claiming that it served a western agenda and didn't devote enough resources to the Communist countries. A similar boycott of the United Nations Security Council prevented them from using their veto to keep the western intervention in the Korean War from happening under a UN mandate, but it took until 1958 for the Russians to decide there might be benefits for them in dipping their toe back into the WHO. And it turned out there were benefits for the rest of humankind, too.

At the time, the United States was invested in a costly and largely ineffective campaign against malaria under the rubric of the WHO. The Soviets, who happened to have most of the world's smallpox vaccine manufacturing capability, pointed out that the efforts of the global health body might be better directed towards smallpox: it was theoretically possible to vaccinate everyone in affected areas and wipe the disease out, whereas mosquitoes could continue to carry malaria indefinitely. The American anti-malaria campaign was actually based on the idea of wiping out mosquitoes, and the Soviet proposal seemed workable by comparison.

However, it took a while for the Americans to come around to the idea. The late 1950s and the early 1960s were a fraught time in the Cold War, a madness that culminated with the Cuban Missile Crisis. The U.S. didn't want to be upstaged by the Soviets, or admit its malaria campaign was misguided - so it told the Soviets that if they were really so serious about global health, they ought to get behind the malaria campaign rather than making silly suggestions.

This stance remained the official line for some years. But three factors gradually intervened. First, the deficiencies of the malaria campaign became obvious. Secondly, tensions between the two superpowers eased. Lastly, the United States realized that the Vietnam War was given it a major public relations headache, and decided to do something about it.

One way to understand the Cold War is as a battle between the Americans and the Soviets for the allegiance of the global south. Both wanted to export their model of civilization, and to demonstrate to countries across Asia, Africa and Latin America that their way of life was best. Part of this was showing off their goodwill and their technical abilities. When the U.S. was faced with a probable Communist takeover of all of Vietnam, it responded with brutal firepower, and it worried that this might damage its image across the rest of the world.

Lyndon Johnson, the American president who decided to escalate the war in Vietnam in a major fashion in 1965, was a liberal who constantly wrestled with his conscience over the war. He liked to see the war as one engagement in the battle to provide a non-Communist route to prosperity and development for Asia and Africa, and he was keen to open other fronts in the war as well. So another decision his administration took in 1965 was to throw the weight of the United States firmly behind a campaign to eradicate smallpox.

Not only did this mean acquiescing in the Soviet call to make smallpox eradication the key thrust of the global health agenda, it also meant cooperation with the Soviets - they had the main sources of vaccine. Of the two billion doses eventually administered, the Soviets manufactured 1.7 billion. The U.S. provided most of the funding. By 1975, smallpox was eradicated.

The campaign against smallpox was not only an amazing example of mankind's ability to overcome an age-old challenge, but also set a precedent for the depoliticization of global public health. The UN has many critics, but the creation of a neutral, non-political space in the form of the WHO allowed politics to be put to one side and a great good done for humankind. Its scale was also telling, and an echo of it can be seen in the millions of people vaccinated against polio annually in India. And it showed what can be accomplished when the leading powers of the world work together, not against one another.

My main source for this write-up is Erez Manela, "A Pox on Your Narrative: Writing Disease Control into Cold War History," Diplomatic History 34:2 (April 2010), 299-323. For understanding related issues in the history of the Cold War as a whole, see Odd Arne Westad, The Global Cold War: Third World Interventions and the Making of Our Times.

A fat is one of the three categories of macronutrient, along with carbohydrate and protein. A fat can also be called a lipid. Fats from vegetable sources are usually liquid at room temperature, while fats from animal sources are usually solid at room temperature, although exceptions exist.

"Fat" is a very old, plain English word, and it is perhaps an unfortunate accident of language that a word with the colloquial meaning of "obese" or "large" has a fairly technical meaning.

All life that we commonly encounter stores or uses energy in the form of carbon chains. Plants produce these carbon chains out of solar radiation and carbon dioxide. Both plants and animals combine molecular oxygen in the atmosphere with carbon chains to create usable energy.

Since our cells are filled with water, the main molecules that is used for making energy are various sugars. Sugars are water soluble, which means a sugar molecule can travel easily through both the cytosol inside a cell and through the bloodstream of larger animals.

But the reason that a sugar is water soluble is because its carbon chain is festooned with hydroxy groups, where an oxygen atom takes a place between a carbon atom and a hydrogen atom. This makes the molecule soluble in water, but it also means that a sugar atom has half the energy it could have. Since the body makes energy by burning carbon chains, a sugar molecule is in effect already half-burnt. This means sugar has half the caloric value of fat, which also means that the body would need twice as much volume to store energy as sugar.

And that is why living things have fats. Fats are a much purer form of energy, consisting of nothing but carbon and hydrogen, ready to be oxidized. _{(Technical Note: For structural reasons, fats are actually stored as fatty acids, which have a few oxygen atoms in them, but that doesn't change their nutritive value).} . When your body has excess sugar, it stores it in the more concentrated form of fat, and when your body needs sugar, it changes that fat back into the water soluble form of sugar. There is a lot of metabolic machinery in all living things designed to shuffle chemical energy from one form to another.

And that is the basic reason for fat. There are other uses that fat is put to, including things like insulation, but the main biological reason for fat is to store concentrated energy.

And how concentrated it is! One of the major dietary problems confronting modern people is just how much energy a small amount of fat can have. For tens of thousands of years, getting too much food was not a problem, and the concentrated energy in fat might make the difference between making it through a cold winter, or not. But in modern times, we have an almost limitless supply of concentrated food energy. Fat has 9 calories per gram. A gram of fat is about one cubic centimeter. This means that a cube 6 centimeters on a side has 216 grams of fat in it. This means that a cube six centimeters on a side of pure fat has around 1950 calories, or about as much as a normal adult would need to eat in a day. The amount of fat needed to sustain life in a day would easily fit in the palm of your hand.

Not that people go around chewing down on pure lard, or sipping table spoons of canola oil, but it does show just how quickly a small amount of fat can add up to many calories. A few tablespoons of oil added to a dish can add 200 or 300 calories. Over time, this fat accumulates and makes people...fat. Since fat is concentrated, it is easy to forget that this is happening.

So fat is a simple biochemical solution to the problem of storing energy, that has made living easier for plants and animals for hundreds of millions of years, and which just in the past few decades has become a major health problem for those of us living in the first world.

Phytoplankton are autotrophic creatures, which means they create their own energy through photosynthesis. Phytoplankton usually reproduce though asexual reproduction and form the base of the aquatic food web. The generational time of phytoplankton is in the order of a few days to a few hours. Marine phytoplankton live in the ocean's photic zone, or epipelagic zone. The light, temperature and nutrient levels in the epipelagic zone are optimal for photosynthesis. Phytoplankton are eaten by zooplankton or are skimmed up by filter-feeders.

Phytoplankton account for over 99% of the plants in the ocean. Large plants, like kelps and seaweeds that inhabit near-shore areas account for the remaining one percent.

Silicate-based organisms
• Diatoms: Diatoms are important geologically because the accumulation on the ocean floor causes a siliceous sediment, or opal deposits. Diatoms are made of frustules, silicate casings that resemble a pill-box. When reproducing by cell division, the parts of the frustule (the epitheca, the larger part, and the hypotheca, the smaller part) separate and each becomes the larger casing on the new cell. As the hypotheca divides, down the generational time, the cell will become too small to be viable. When this occurs, the diatom produces an auxospore. An auxospore is a diatom that sheds its frustule to allow growth to a full size diatom, so that normal reproduction by shedding of the frustule can recommence.


Calcium carbonate-based organisms
• Coccolithophores: these phytoplankton have flagellum, little whip-like locomotive structures. Coccolithophores sediment out into large calcium carbonate deposits in the temperate and warm parts of the oceans.



• Dinoflagellates: These phytoplankton possess flagella for movement, and are covered in cellulose (so no mineral deposits occur when dinoflagellates sink). Red tide is caused by two genera of dinoflagellate, Ptychodiscus and Gonyaulax.