GEN-ERIC News

U.S. scientists have overcome a problem involved in optical technology by creating a way to predict the behavior of light emitted on the nanoscale. Nanolight behaves much differently as its wavelength is interrupted, producing unstable waves called evanescent waves. The direction of those unpredictable waves can’t be calculated, so researchers must design nanotechnologies to work with the tiny, yet potentially useful, waves of light. Georgia Institute of Technology scientists have discovered a way to predict the behavior of light waves during nanoscale radiation heat transfer, thus opening the door to the design of a spectrum of new nanodevices and nanotechnologies, including solar thermal energy technologies. This discovery gives us the fundamental information to determine things like how far apart plates should be and what size they should be when designing a technology that uses nanoscale radiation heat transfer, said Professor Zhuomin Zhang, a lead researcher on the project. “Understanding the behavior of light at this scale is the key to designing technologies to take advantage of the unique capabilities of this phenomenon.

Verbs evolve and homogenize at a rate inversely proportional to their prevalence in the English language, according to a formula developed by Harvard University mathematicians who’ve invoked evolutionary principles to study our language over the past 1,200 years, from “Beowulf” to “Canterbury Tales” to “Harry Potter.” Writing this week in the journal Nature, Erez Lieberman, Jean-Baptiste Michel, and colleagues in Harvard’s Program for Evolutionary Dynamics, led by Martin A. Nowak, conceive of linguistic development as an essentially evolutionary scheme: Just as genes and organisms undergo natural selection, words – specifically, irregular verbs that do not take an “-ed” ending in the past tense – are subject to powerful pressure to “regularize” as the language develops. “Mathematical analysis of this linguistic evolution reveals that irregular verb conjugations behave in an extremely regular way – one that can yield predictions and insights into the future stages of a verb’s evolutionary trajectory,” says Lieberman, a graduate student in applied mathematics in Harvard’s School of Engineering and Applied Sciences and in the Harvard-MIT Division of Health Sciences and Technology, and an affiliate of Harvard’s Program for Evolutionary Dynamics. “We measured something no one really thought could be measured, and got a striking and beautiful result.” “We’re really on the front lines of developing the mathematical tools to study evolutionary dynamics,” says Michel, a graduate student in systems biology at Harvard Medical School and an affiliate of the Program for Evolutionary Dynamics. “Before, language was considered too messy and difficult a system for mathematical study, but now we’re able to successfully quantify an aspect of how language changes and develops.” Lieberman, Michel, and colleagues built upon previous study of seven competing rules for verb conjugation in Old English, six of which have gradually faded from use over time. They found that the one surviving rule, which adds an “-ed” suffix to simple past and past participle forms, contributes to the evolutionary decay of irregular English verbs according to a specific mathematical function: It regularizes them at a rate that is inversely proportional to the square root of their usage frequency.

Tooth loss may predict the development of dementia late in life, according to research published in the October issue of The Journal of the American Dental Association (JADA). Numerous past studies have shown that patients with dementia are more likely than patients without the condition to have poor oral health. Few researchers, however, have examined the relationship from the opposite direction, to determine whether poor oral health actually may contribute to the development of dementia. To that end, researchers from the University of Kentucky College of Medicine and College of Dentistry, Lexington, studied data from 144 participants in the Nun Study, a study of aging and Alzheimer’s disease among Catholic sisters of the School Sisters of Notre Dame. The researchers used dental records and results of annual cognitive examinations to study participants from the order’s Milwaukee province who were 75 to 98 years old. “Of the participants who did not have dementia at the first examination, those with few teeth (zero to nine) had an increased risk of developing dementia during the study compared with those who had 10 or more teeth,” the authors write.

The reason why even professional basketball and soccer players sometimes miss an easy shot may be partly explained by spontaneous fluctuations of electrical activity within the brain, a study suggests. An experiment conducted by researchers at Washington University, in Missouri, US, found that fluctuations in brain activity caused volunteers to subconsciously exert slightly less physical force when pressing a button on cue. Crucially, this activity is independent of any external stimulus and does not appear related to attention or anticipation. The scientists involved say it is the first direct evidence that internal instabilities – so-called “spontaneous brain activity” – may play an important role in the variability of human behaviour. From the mid-1990s onwards, brain-scanning techniques have revealed variable brain activity that appears unrelated to external stimuli and occurs even when a person is asleep or anaesthetized.