Scientists are providing a fuller understanding of the essential role that sleep plays in brain health, identifying an abrupt transition at about 2.4 years of age when its primary purpose shifts from brain building to maintenance and repair.
Researchers on Sept. 18 said they conducted a statistical analysis on data from more than 60 sleep studies. They looked at sleep time, duration of rapid eye movement (REM) sleep, brain size and body size, and devised a mathematical model for how sleep changes during development.
There are basically two types of sleep, each tied to specific brain waves and neuronal activity. REM, with the eyes moving quickly from side to side behind closed eyelids, is deep sleep with vivid dreams. Non-REM sleep is largely dreamless.
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During REM sleep, the brain forms new neural connections by building and strengthening synapses — the junctions between nerve cells, or neurons — that enable them to communicate, reinforcing learning and consolidating memories. During sleep, the brain also repairs the modicum of daily neurological damage it typically experiences to genes and proteins within neurons as well as clearing out byproducts that build up.
At about 2.4 years of age, the findings showed, sleep’s primary function changed from building and cutting connections during REM sleep to neural repair during both REM and non-REM sleep. “It was shocking to us that this transition was like a switch and so sharp,” said Van Savage, a UCLA professor of ecology and evolutionary biology and of computational medicine who is a senior author of the research published in the journal Science Advances.
REM sleep declines with age. Newborns, who can sleep about 16 hours daily, spend about 50 percent of their sleeping time in REM, but there is a pronounced drop-off at around 2.4 years. It drops to about 25 percent by age 10 and to about 10 percent to 15 percent around age 50. “Sleep is required across the animal kingdom and is nearly as ubiquitous as eating and breathing,” Van Savage said. “I’d say it is a pillar of human health.”(Reuters)
Translation can be a tricky business. Some words and expressions have a clear equivalent in another language, but others just don’t translate easily. Here are a few Chinese ones with cultural connotations that make them hard to express simply in English. Ji? You Literally, this means “add oil,” but this phrase is frequently used as encouragement. Depending on the context, the expression can also be used to cheer people up after a disappointment, or wish people good luck. In English, each of these situations has its own saying. Xiao Shun Your parents will approve of this phrase. The plain translation is simply “filial”—
Greece has become the first majority-Orthodox Christian nation to legalize same-sex marriage under civil law. At least for the near future, it will almost certainly be the only one. Eastern Orthodox leadership, despite lacking a single doctrinal authority like a pope, has been united in opposing recognition of same-sex relationships both within its own rites and in the civil realm. Public opinion in majority Orthodox countries has mostly been opposed, too. But there are some signs of change. Two small majority-Orthodox countries, Montenegro and Cyprus, have authorized same-sex unions in recent years, as did Greece in 2015 before upgrading to full marital
A: This medical paper, titled “Structural basis for the allosteric modulation of rhodopsin by nanobody binding to its extracellular domain,” is quite interesting. B: What’s it about? A: Researchers from UC Irvine have discovered a special antibody that may lead to a treatment for retinitis pigmentosa. B: What’s retinitis pigmentosa? A: It’s an illness that causes the loss of central vision, as well as night and color vision. A: 這篇醫學報告蠻有意思的，標題是︰《細胞外區奈米抗體與視紫紅質異位調節之結構基礎》。 B: 主要在講什麼？ A: 加州大學爾灣分校研究員們發現了特殊抗體，有望治療「色素性視網膜炎」。 B: 「色素性視網膜炎」？ A: 這種疾病會導致中央視力、夜視和色覺喪失。 （By Eddy Chang, Taipei Times／台北時報張聖恩）
A: Retinitis pigmentosa is often caused by rhodopsin mutations. B: What have UC Irvine researchers discovered in this study? A: They found a llama-derived antibody, known as a nanobody, that can halt the process of rhodopsin photoactivation. B: That’s something new. A: And the stabilizing effect of such nanobodies can be applied to rhodopsin mutants. A: 「色素性視網膜炎」通常是視紫紅質突變引起的。 B: 這次加州大學爾灣分校的研究有什麼新發現？ A: 他們發現了一種羊駝衍生抗體，稱為「奈米抗體」，能停止視紫紅質光敏化的進程。 B: 真新奇。 A: 奈米抗體的穩定作用，還可望治療視紫紅質突變。 （By Eddy Chang, Taipei Times／台北時報張聖恩）