Science Square

  • Issue 82 / July - August 2011



    Writing of Our Worries

    The Fountain

    1- Writing of Our Worries
    Original Article: Ramirez G. et al., Science 331, 211 (2011).
    We have had to deal with tests and exams in academic and professional life from childhood on. Though we are motivated to perform our best, the pressure-filled situations generally cause us to perform below our abilities. University of Chicago researchers were interested in finding an intervention that would improve performance under such conditions, especially for those students who do not do well on exams because they are blocked by anxiety. Their study showed that simply writing down our thoughts and concerns immediately before a high-stress event can increase performance from 5–12 percent when it matters most. The simple brain-focusing exercise of writing down feelings for ten minutes before an exam reduces anxiety and increases exam scores significantly. The researchers concluded that writing allows individuals to reexamine the situation and revaluate concerns, reducing anxiety and increasing one’s ability to focus. This type of writing may help people perform their best not only on tests but also in variety of high-stress situations—a big presentation to a client, a speech to an audience, or even a job interview.

    2- Life Without Starlight
    Original Article: Hooper, D. & Steffen, J.H. (arXiv:1103.5086v1).
    Liquid water is considered the common solvent to catalyze carbon-based life on planets. This assumption defines a rather tight region around stars, which is called the “habitable zone.” The energy absorbed from the host star through its light allows planets in the habitable zones to melt water into liquid. Water would either evaporate or remain ice if the planet is too close to or distant from the star. A recent study suggested that starlight may not be the only energy source that can convert ice into liquid water and maintain it in that state. Dark matter annihilation may produce enough heat in special circumstances for planets that may not be sufficiently heated by their host star. Ordinary matter constitutes only about 20 percent of the matter in the universe, while dark matter makes up about 80 percent of all matter. It is believed that dark matter weakly interacts with atomic nuclei. Therefore, one of the leading models for dark matter is called “weakly interacting massive particles” (WIMPs). In cases where dark matter interacts with nuclei, WIMPs can transfer momentum to the nucleus. Then they can get gravitationally captured and subsequently decay as energetic particles. This process can produce heat as a consequence. On Earth, the concentration of dark matter at its center is not sufficient to produce observable contributions to the planet’s total heat budget. However for planets around stars that are closer to the centers of their galaxy, where the concentration of dark matter is significantly higher, just enough heat may be produced by gravitationally captured and annihilated dark matter. The abundance of planets detected by NASA’s satellite mission-Kepler suggests that perhaps life in the universe might be more abundant than we thought.

    3- How Much Digital Information Can Mankind Store?
    Original Article: Hilbert, H. & López, P., Science 332, 60 (2011).
    Have you ever wondered how much total information is stored by human beings? We store information in two different forms: analog storage such as books, printed photos, and audio cassettes, and digital storage such as hard drives, CDs, DVDs, and the like. A recent paper analyzed how the total information storage and processing ability of human beings changed between the years of 1986 and 2007. The study estimated that the total information stored as of 2007 is 295 exabytes. An exabyte is equal to one million terabytes or one billion gigabytes. If all this information was stored on CDs, this stack of CDs would reach beyond the moon. If it was stored in books, it would be enough to cover the entire United States with 13 layers of books. Interestingly, the information stored by DNA in one single human body is about 300 times larger than the entire amount of information stored by humanity. In 2000, only 25 percent of known information was stored in digital form; this ratio increased to 94 percent in 2007. The area in which the “information revolution” is most evident is computation. The study found that the global computing capacity increased by 58 percent per year during this time. But even at this fast rate of growth, in 2007 the total instructions per second that humankind can carry out on its general-purpose computers were about the same as the maximum number of nerve impulses executed by one human brain per second.

    4- Tricking the Brain to Attack Alzheimer’s Disease
    Original Articles: Atwal, J. K. et al., Science Translational Medicine 3, 84ra43 (2011) & Yu, Y. J. et al., Science Translational Medicine 3, 84ra44 (2011).
    Alzheimer’s disease affects many people, especially in later stages of life, and as the lifespan of humans increases, it becomes much more prevalent everyday. The primary cause of Alzheimer’s disease is unknown, but scientists generally associate the disease with the appearance of plaques and tangles in brain cells, often caused by a protein called amyloid. Hence, a natural strategy would be to attack these proteins that form these plaques. Yet, the biggest obstacle in our brain is the blood-brain barrier, which prevents viruses and other unwanted visitors from entering our most delicate organ. Scientists have tried to overcome this barrier with many different drugs and strategies, but there is no clear winner yet. Two recent studies reported in Science Translational Medicine journal give us a new hope in our fight against Alzheimer’s disease. Scientists devised a clever strategy to trick the gatekeepers of the blood-brain barrier into escorting antibodies against the Alzheimer’s-associated proteins. This method reduced the levels of amyloid by up to 50 percent inside mouse brain cells. Designed antibodies had two arms—one arm to target the enzyme, BACE1, which produces the amyloid, and the other arm to bind to the transferring receptor, which in turn deceived the endothelial cells from the blood-brain barrier to internalize the antibody. There are many other brain disorders that we have a limited arsenal against because of the blood-brain barrier. Hence this new method can be used for these diseases, which opens up a whole new venue of targeting strategies.

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