Sleep
睡眠新知
Key to a Good Night’s Sleep Is In Your Brain
想要一夜好眠？其實關鍵就在你自己的大腦裡
An uninterrupted night of sleep is a rare commodity—what with TVs blaring, toilets flushing and the occasional plane flying overhead. The sleeping brain is designed to tune out these auditory distractions, but some people’s brains do so a lot better than others’. Now researchers have the first clues to understanding why.

晚上不被打斷的睡眠，對許多人來說是一種奢求。舉凡電視的喇叭聲、沖馬桶的噪音、還有時而從你頭上呼囂而過的飛機，都可能成為打斷你睡眠的因素。其實睡眠中的腦，可以自動將這些惱人的噪音排除在外，只是有些人能夠做得比其他人還要好。現在，科學家找到了一些初步的線索了解其中的原因。

Scientists at Massachusetts General Hospital analyzed the brain waves of 12 self-described healthy sleepers during a three-night study in a sleep lab. The volunteers were given cozy beds, but throughout the night they were assaulted with 14 sounds—including car traffic, airplane noise and slamming doors—piped through speakers at varying volumes.

麻州總醫院分析了12位自稱睡眠習慣品質良好的人，讓他們在一間睡眠研究室睡三個晚上。醫院提供他們溫暖舒適的床，但在睡覺的時候，會有高達14種不同的噪音來擾亂他們，包括了汽車聲，飛機聲和猛然關門的聲音，這些噪音會以不同的音量透過音響傳到他們的睡眠室。

It turned out that those who dozed through the loudest noises were those whose brains recorded the most “sleep spindles” on EEG. Scientists say the spindles, produced by activity in the thalamus (a region deep in the brain that processes incoming stimuli), can be used as a measure of how well the brain blocks out sound during sleep. And someday, they say, they may be able to manipulate spindle activity to help light sleepers catch more zzz.

結果發現，那些曝露在最大噪音下，仍可睡得很安穩的人，在腦電波分析儀上測到的「睡眠紡錘波」，相較於其他人是最高的。科學家說，所謂的紡錘波，就是視丘(大腦深處，一個用來處理外來刺激的區域)活動所產生的物質，可以用來衡量大腦在睡眠時，將噪音排除在外的能力。他們也說，或許有一天，可以人為操控睡眠紡錘波，來讓那些淺眠的人們能夠擁有更好的睡眠品質。

Pregnant
懷孕新知
The World Health Organization advises women who miscarry to wait at least six months before getting pregnant again. But new research from Scotland found that women who conceived within six months of miscarrying had the best chance of a successful pregnancy. The age of the women may have been the driving factor in the study: the longer older women wait to try again, even by a few months, the higher their risk of having another miscarriage.

世界衛生組織建議，流產過後的女人應至少等待六個月後再懷胎。但一個蘇格蘭最新的研究指出，女人在流產過後六個月內，才是最佳的懷孕成功時機。而女人的年齡，也是影響此研究的一個因素：較年老的女人如果隔了越久才懷孕，即使才多幾個月，那麼她們再次流產的風險就更高。

Sexual Health
兩性健康
Are Girls Entering Puberty Too Soon?
現在的女孩們是不是太早進入青春期了？
A new report finds that girls in the U.S. are more likely than they were a decade ago to develop breasts as early as age 7. The study is the latest in a growing body of research that suggests girls may be hitting puberty at ever earlier ages, prompting experts to wonder, How young can you go?

一項新的報告發現，美國女孩的胸部，比起十年前有提早發育的現象，其中最早的從7歲就開始發育。這項報告來自於一項人體發育研究，報告指出，現在的女孩子可能是有史以來最早進入青春期的女孩，這也引起了專家的好奇，到底青春期還能夠提早多久發生？

The report, which examined girls from 2004 to 2006, found the trend particularly striking among white girls, who were nearly twice as likely as girls in 1997 to show breast development by age 7. But the study also hinted that some girls have reached the minimum age for sexual maturity: African-American girls were no more likely to show early breast development than they were a decade ago, possibly because they can’t begin puberty any younger.

這項報告研究了2004到2006年的女孩子，發現這個現象對於白人女孩來說，尤為顯著。她們在7歲即有胸部發育現象的人數，比起1997年的女孩，多了將近2倍。但這個研究也發現，有些種族的女孩已經到達了性徵成熟的最小年紀：非洲裔的美國女孩，比起十年前來說，她們胸部發育的年紀不會再更小了，這可能是因為她們無法再更提早進入青春期。

Early puberty can be worrisome because estrogen, the hormone responsible for breast development and sexual maturity, also contributes to breast cancer. The longer a girl’s body is exposed to estrogen, the greater her risk of cancer may be as an adult.

為何提早進入青春期會如此讓人擔心？因為促使胸部發育及性徵成熟的賀爾蒙－雌激素，也與乳癌息息相關。一個女孩子體內越早出現雌激素，則她長大成人後罹患乳癌的風險也越高。

What’s prompting the shift? The authors speculate that a major cause of early puberty is obesity, since fat deposits produce sex hormones and trigger sexual development. But exposure to environmental sources of estrogen-mimicking chemicals like food additives and endocrine disrupters like BPA may also play a role.

而到底是什麼原因引發如此的變化？研究人員推論，造成性早熟的最主要原因可能是「肥胖」，因為脂肪的堆積會產生性激素，且同時也會促成性徵的發展。另外曝露於生活環境中「類雌激素」的食品添加物，及內分泌干擾物質如雙酚A等化學物質，也是造成性徵早熟的可能原因。

From The Labs
生物新知
Reviving Old Cells
老化細胞的再生
Newts and Salamanders may sit lower on the evolutionary tree than mammals, but they can do something mammals can’t: regrow damaged or missing limbs. Researchers have now found a way to coax muscle cells in mice to perform the same regenerative trick, by turning off genes that limit cell growth. Scientists still need to ensure that they can deactivate those genes only temporarily; otherwise he muscle cells may start to divide uncontrollably, leading to cancer.

蠑螈類的生物，或許在生物演化樹中，較哺乳類動物的地位低，但牠們能夠做到一些哺乳類動物無法做到的事，像是讓受傷或截斷的四肢再生。科學家發現了一種技術，將停止細胞生長的基因拿掉，如此就可以讓老鼠的肌肉進行相同的細胞再生。而科學家也必須確定他們將基因拿掉只是暫時性的，否則細胞可能會無止境地不斷生長，進而造成癌細胞的產生。

Alzheimer’s Test?
提前預知阿滋海默症？
Specific proteins found in the spinal fluid may help identify people with Alzheimer’s years before they develop the disease, according to a study. The test is unproven, and there are no treatments yet for people who are positive, so it is currently being used only for research.

某項研究指出，特定的腦脊液蛋白可能會幫助人們在他們發生阿滋海默症的幾年前預知。但這項研究尚未經過證實，而且也沒有臨床實驗指出有任何人有相關的陽性反應，所以目前這項報告正處於研究階段。

A Mating Race
求偶競爭
Competition may be good for the soul, but not so for the life span, according to a study on longevity. Men who grew up in places where males outnumbered females—and thus had to compete for mates—lived on average three months less than those who came of age in an environment with a more even sex ratio. The authors say the stress of fending off rivals may explain the shorter life spans.

根據一項有關長壽的研究指出，競爭，可能對於心靈來說有所幫助，但對於延年益壽，就不是那麼一回事了。對於男人來說，生存於同性人數多過異性人數的環境－進而造成所謂的求偶競爭－會使他們相對於那些生長於男女比例相近的環境的男人，短少平均約三個月的壽命。研究人員指出，防禦同性敵人的壓力，可能是造成較短命的主因。