Selected Stuff from 2013
CHAPTER 41 Goodbye 2013
At the end of each year, I look forward to Discover magazine's 100 top stories of the year. I was happy to see that in the January/February 2014 issue Discover chose as the number one story of 2013 the Mars rover Curiosity finding the most convincing evidence that life could have existed on Mars in the far distant past. Curiosity, after finding what was once a streambed with flowing water, then drilled into the Martin mudstone rock and analyzed the sample. Curiosity reported the finding of various elements such as carbon, hydrogen, sulfur, oxygen and phosphorus, along with sulfur dioxide and hydrogen sulfide that could have been sources of energy for microorganisms. At the same time, Curiosity found no methane in the atmosphere, not a good sign that any microorganisms are hanging around today.
The Curiosity mission also provided evidence that the shielding needed to protect any astronauts from radiation on a Mars expedition would have to be much better than currently available. In the past, I have expressed skepticism about the possibility of a manned flight to Mars, although I once would have enthusiastically favored such a mission. If we really hope to find life on another heavenly body it seems to me we should abandon Mars and focus on Jupiter's moon, Europa. Last month, NASA announced that the Hubble telescope had found evidence of a geyser of water erupting from Europa. The jets of water reached a height of over a hundred miles.
It's been known for some time that there's an ocean of water deep under the surface of Europa and hence the possibility of life. Since the water that erupts could contain any such life, there's the possibility that a Europa mission could either sample the frozen water fallen back to the surface or, if extremely lucky, catch some of the water in a plume during an eruption. Caution - apparently, Hubble has only seen one of these eruptions and NASA will be working hard to confirm any future eruption and also examine its records to see if there's evidence of a past eruption.
In addition to Discover's top stories, at the end of a year I also look forward to the journal Science and its "Breakthrough of the Year". In contrast to Discover's top story, Science's breakthrough is a much more down-to-earth choice - Cancer Immunotherapy. Science reports that the selection of cancer immunotherapy was made with quite a bit of internal debate. This approach to fighting cancer has been around for quite some time, with mixed results, but the Science crew decided that in 2013 "clinical trials have cemented its potential in patients and swayed even the skeptics."
What is cancer immunotherapy? Instead of using drugs or radiation to fight cancer, the idea is to use the body's immune system, notably T-cells, to go after cancer. It seems that it all started back in 1987 when French researchers identified a new protein receptor on the surface of T cells. James Allison, now at the University of Texas MD Anderson Cancer Center in Houston, found that the protein, called CTLA-4, diminished the strength of the T cells in attacking the cancer. In 1996 Allison reported in Science that by using antibodies against CTLA-4, in other words blocking the blocker, the T cells killed tumors in mice.
Since then, another molecule known as PD-1 has joined CTLA-4 as a known brake on T cells fighting cancer. Using anti-PD-1 and anti-CTLA-4 antibodies, physicians were amazed to find that in some patients their tumors would continue to grow after the treatment with the antibodies was finished but then disappear later. It was as though the immune system took time to build up to full strength after the treatment. Another approach to immunotherapy is to harvest a patient's T cells and genetically modify them to fight the cancer upon injecting them back into the patient. All these approaches to cancer immunotherapy have had their amazing successes and their failures, which, based on the statistics in the Science article, far outnumber the successes. However, in a field where virtually every patient died a short time after diagnosis, success rates of 15 to 30 percent for different cancers are truly impressive and inspire confidence that immunotherapy offers great promise for the future.
Finally, with the end of 2013, I was reflecting on the various subjects I've considered in these columns the past year and wondering what I would choose for my story of the year. I decided that, aside from my obsession with anything related to space and the universe, I most enjoyed and was most intrigued by the monarch butterfly (see archives for column posted on 5/31/2013). I found it astounding that one species could in four generations make a round trip from Mexico to the upper reaches of the United States and even Canada; the astounding part to me was that one of these generations could modify its characteristics in a way that permitted that generation to make the whole journey from up north down to Mexico.
Accordingly, I was saddened to read in an article by Jim Robbins in the November 24 New York Times that the monarch appears to be in trouble. In Mexico, November 1 is the day when millions of monarch butterflies arrive in the mountainous fir forests in central Mexico. November 1 is also a holiday known as Day of the Dead, a day when Mexicans recall and honor their deceased relatives and ancestors. Well, this past year the monarchs did not arrive on November 1 but started to appear a week later than usual and in vastly reduced numbers - an estimated 3 million, compared to the normal number of some 60 million butterflies. Are the monarchs, like the honeybees, in trouble? In the article Robbins points out the loss of habitat and food sources for the butterflies on their long journey. He attributes much of that loss to the increase in the emphasis by farmers in the U.S. on growing corn to avail themselves of government subsidies related to biofuels. The expansion of farms for this purpose has resulted in the loss of vegetation, notably milkweed, critical to the raising of generations of monarch butterflies.
Another insect I enjoyed writing about was the dung beetle, which guides its path home with its treasure of dung by way the light of the Milky Way. I'm guessing that my tendency to write about animal life is at least partly due to the fact that, in my advancing years (I turned 86 since my last column), I'm able to understand the stories about animal life. It's a lot easier to understand than biochemistry or quantum computing, subjects I have written about in my younger days.
Another animal that I find intriguing is the owl. In a recent meeting of the Old Guard of Summit group to which I belong, an enthusiastic young man from the Raptor Trust, Ben Montgomery, gave a most interesting talk about raptors, including then owl. Montgomery brought with him a tiny owl, call him Winky, which was about four years old and had been hit by a car some years earlier. The Trust cares for wounded raptors and the tiny owl, about 6 inches tall I estimate, will live out his life under their care. Montgomery carried Winky around the room on his wrist and the owl kept his eye (he was blind in the other eye due to the accident) on the speaker continuously as he was carried around and when he was tethered to a perch on a table in front of the room.
As with other owls, Winky could turn his head around almost all the way when he followed Montgomery around the room. We learned that the reason owls can accomplish this feat is that they have 14 neck bones whereas we humans have only seven. The owls long neck isn't apparent to us because of its feathers hiding its neck. The owl's eyes are fixed; hence the reason they must turn their heads to focus on an object catching their attention. If you look at the pupils of their eyes you may see that one pupil is open larger than the other. The owl can control the sizes of their pupils independently to better focus on the subject. The owl's eyes are huge for the size of an owl. If our eyes were of the same proportion to our head size as the owl's, our eyes would be the size of a grapefruit!
Finally, let's look at the owl's hearing. The owl's ears, unlike ours, are not symmetrically located on their heads, one being offset from the other. Hence, the sound from, say a mouse or other animal scurrying around under a layer of snow, arrives at one ear a tiny fraction of a second sooner than at the other. If the owl turns its head so that the sound arrives in both ears at the same time, the owl's head is now positioned so it's looking directly at the animal, which could become a nice meal for the raptor!
Well, so much for my yearend musings. Next column, hopefully, will be posted on or about February 1, 2014. Happy New Year!
Allen F. Bortrum