This "Ladybird" roams the farmland, gives you fertilizer if you are seen as a crop, and shoots weed killer if it thinks you are a weed.
2016年4月30日 星期六
Why are peacock tail feathers so enchanting?
http://www.pbs.org/newshour/rundown/why-are-peacock-tail-feathers-so-enchanting/
Why are peacock tail feathers so enchanting?
JULIA GRIFFIN
“The sight of a feather in a peacock’s tail, whenever I gaze at it, makes me sick,” Charles Darwin told a fellow scientist in a letter in 1860.
The showiness of the peacock tail initially struck him as a handicap — why would an animal put so much energy into producing a purely ornamental feature? — but it would come to embody an important part of his theory of sexual selection.
Today, 150 years later, peacock tails haven’t been terribly well researched. To understand the role they play in sexual selection, scientists studied feather length and they studied the number of eyespots, and neither proved to play a major role in wooing.
Now, a group of interdisciplinary scientists have turned their attention to another factor: the almost hypnotizing shaking of the long tail feathers known as “train-rattling.” The findings were published April 27 in the journal PLOS ONE.
A 2013 study found placing stickers over a male peacock’s iridescent eyespots caused mating success to drop to nearly zero. Photo by Roslyn Dakin
Train feathers are the the long, quintessential green, blue and bronze plumes that made the male peacock famous. In train-rattling, the bird shakes the train feathers to create a shimmering, iridescent background while the eyespots appear motionless.
Researchers filmed male and female peacocks at a botanical garden near Los Angeles with high-speed cameras. When train-rattling, the birds used the shorter, grey tail feathers to strum the longer feathers like a guitar. On average, they did it at a rate of 25 times a second.
Like a parent pushing a child on a swing, the male’s tail feathers vibrate the plumes in an energetically efficient manner. The strumming even produces a percussive, rustling sound.
But why the eyespots stand relatively motionless while the feathers move required more explanation.
Back in the lab, the team mechanically shook individual train feathers to measure their vibration. Shorter feathers shook at a higher resonant frequency than longer feathers. The effect is analogous to a musical tone made on a violin as compared to a cello. A pluck of a violin’s shorter string produces a higher pitch at a higher resonant frequency than the same motion on the longer strings of a cello.
The difference in frequencies was smaller than fellow author and physicist Suzanne Amador Kane expected, and the eyespots remained practically stationary only at the resonant frequencies observed in train-rattling.
Kane said two factors were at play. First, the loose barbs along the feathers’ length cause friction that altered the vibration action.
“They are rubbing against each other, and it turns out when you have a lot friction in the system, that allows you to excite the frequency over a broad range,” Kane said. “So instead of having one frequency that works like a bell with a very clear note, it turns out that when you have a lot of friction, you have a range of frequencies.”
Images taken by a scanning electron microscope also revealed tiny hook-like feathers on the eyespots. These hooks anchor the end of the train feather, creating a perception of stillness.
Iridescence too, seems to play a role. In a 2013 study, Biologist Roslyn Dakin found that iridescence — the change of an eyespot’s hue in relation to light angle — explained about half of mating success. Place stickers over the male’s eyespots, and mating rates drop to near zero.
But how train-rattling factors into sexual selection remains to be seen. Because the team did not factor mating success into this study, future research could investigate how iridescence and shaking work together to catch a female’s eye. Scientists could also explore why larger birds shook their feathers faster than predicted in the lab, and whether that is significant in mate selection.
Either way, Kane is pleased the research can help advance an age-old mystery.
“It’s cool that this is a system Charles Darwin talked about so long ago when he was thinking through theories of natural and sexual selection,” she said. “[He] posed peacocks as a problem then, and here in 2016, we can say something new.”
2016年4月29日 星期五
Understanding gravity: From Newton to Hawking
Understanding gravity: From Newton to Hawking
Cambridge University Library is celebrating its 600th anniversary with an exhibition of priceless treasures communicating 4,000 years of human thought. To celebrate, we have made six films on the six distinct themes featured in Lines of Thought. The second film in the series looks at Gravity; by following the discussions of generations of great scientific minds, from Copernicus to Hawking via Newton and Einstein, we begin to understand our place among the stars.
Why drinking red wine and eating chocolate may be good for your gut
In two new studies, scientists take a big step toward understanding how our little passengers can make big changes in our lives.
2016年4月27日 星期三
Neuroscientists create ‘atlas’ showing how words are organised in the brain; Speakers of two dialects may share cognitive advantage with speakers of two languages
Scientists have created an “atlas of the brain” that reveals how the meanings of words are arranged across different regions of the organ.
2016年4月25日 星期一
小小鐵絲讓尼泊爾房屋變得更加堅固 (薩希特)
德國之聲
科技環境
小小鐵絲讓房屋變得更加堅固
一年前的今天尼泊爾發生里氏7.8級強震，地震造成近9000人死亡，大量災民無家可歸。現如今一名在德國生活的尼泊爾人找到了一種讓房屋變得更為堅固的建築方法，讓尼泊爾人住得更加安全。
（德國之聲中文網）星期六的中午，薩希特坐在位於加德滿都的家中。他一周工作6天，只有星期六是休息日。一家人剛吃過午飯，下午準備去看望叔叔。薩希特盤腿坐在地上看報紙，突然家裡所有的家具都劇烈地晃動起來。這一天就是2015年的4月25日。薩希特說："我立刻就知道是地震了。我們在尼泊爾經常經歷地震，但是像這一次這麼大規模的地震我還是頭一次遇上。地震震得我分不清東南西北，連站都站不起來。當時我覺得自己可能活不下來了。"直到一年後的今天，地震時的情景仍然深深地印在薩希特的腦海裡。
薩希特講述說，後來他終於站直了身子，搖搖晃晃地走到父母的房間。一家人跌跌倒到地跑到外面。薩希特家的房子蓋得比較堅固，在這場大震中只出現了幾條裂痕，但是房子並沒有倒塌。但是很多人家在這場震級強度達到7.8級的地震中並沒有薩希特家那麼幸運。無論是在首都加德滿都還是在鄉村地區，隨處都可以看到房倒屋塌的慘狀。地震發生兩週後，一場幾乎震級相同的餘震再次讓災民們驚恐不已。去年4月發生的強震在尼泊爾總共奪走了近9000條生命。
去年尼泊爾地震造成近9000人死亡
1997年，薩希特來到德國亞琛學習醫療技術。現如今年近40歲的他已經是兩個女兒的父親，一家人生活在科隆附近。幾年前他創辦了自己的IT公司，研發麵向工程師和設計師群體的軟件程序。這家公司在德國和尼泊爾都設有辦公室，所以每年薩希特要在德國和加德滿都之間來回飛個4、5次。去年4月，他原本只打算在加德滿都停留2週的時間，但是由於地震的發生卻在那里呆了1個多月。
地震發生後的幾晚，薩希特一家人都在街上過的夜。周圍的鄰居也是如此。他們用硬紙板搭了一些臨時帳篷。薩希特慶幸自己活了下來，他決定伸手去幫助其他人："我們家很多親戚都是建築工程師或者在建築行業工作。我在這樣一種環境下長大，所以對這個行業略有了解。小時候我就看得懂建築圖紙了。"
"我們這裡很多人根本不重視基本的建築規則。他們蓋房的時候就地取材，"薩希特說，"有的人打地基的時候就是磚摞磚，根本沒考慮過承重的問題。這樣的房子怎麼可能結實得了？"
薩希特
另外通常情況下地震多發生在季風時節。季風天氣帶來豐沛的降水，土地變得更為鬆軟。很多人家蓋的房子使用的是粘土，這種材質在潮濕的天氣下吸收大量水分，房屋建築反而變得更加柔性。但是去年4月的地震卻發生在旱季。土地和建築都乾涸而堅硬。地震發生時一片房倒屋塌。
薩希特回到德國後開始考慮，如何幫助經歷過地震災難的災民。他所參與的德國-尼泊爾友好協會以及在德國尼泊爾人圈總共為地震災民籌集了2.5萬歐元的捐款。這些錢不僅要用於幫助災民修建臨時房屋和新居，同時還需要用來為受災兒童購買學習材料以及新衣服。不過對於薩希特來說，最重要的是讓倖存者了解掌握建築知識，這樣才能修建更堅固的房屋，在以後的災害中更好地保護自己。
薩希特找到一種簡單的材料，但是卻能更好地加強房屋的堅固度。這種材料就是鐵絲。鐵絲便宜、易加工，運輸也很方便。
用鐵絲編織的網子將磚頭石塊圍罩起來，這樣可以讓建築物變得更具柔韌性也更為堅固。鐵絲網可以防止地震發生時磚牆崩裂倒塌。薩希特說，最好在砌牆的時候再使用相應的木料進行加固。但是可惜當地這樣的材料很少，一般都用來搭房頂，而竹子又不合適搭"骨架"。
用鐵絲編織的網子將磚頭石塊圍罩起來，這樣可以讓建築物變得更具柔韌性也更為堅固。
蓋這樣一座用鐵絲網加固的房屋並不會比在尼泊爾當地蓋一座傳統式的房屋花費更多。薩希特說："我們付了一部分材料費，而且還提供工具。受災地區提供一部分資金，剩餘的部分原本應該由政府出，但是直到現在這些計劃都很難實施。"國際社會為尼泊爾的地震災民捐了數十億的救援款，但是災民們一直沒有獲得真正的救助，就因為救援款項物資的分發一直拖拖拉拉。
再加上尼泊爾國內政局不穩，更加大了救助災民的難度。不過薩希特仍然堅持向災民提供幫助。現如今他已經在加德滿都方圓100公里的地區新蓋了40、50座住房。
在被問到這些新房子是不是可以抵抗得住強震的問題時，薩希特說，當然沒有人能保證這些房子一定不會在地震中倒塌，但是至少可以在地震發生時給住戶提供更多的時間跑到安全的地方，而不是直接被活埋在自己倒塌的家裡。
2016年4月19日 星期二
5G is looming, but network innovations are needed far more urgently
有意思的公司公司併購。Google買Motorola，再將硬體轉賣聯強.....全球衛星通信.....
Nokia 賣手機事業部給Microsoft....買Lucent (含貝爾實驗室，原AT&T.....)
Nokia 賣手機事業部給Microsoft....買Lucent (含貝爾實驗室，原AT&T.....)
Nokia，旗下的Bell Labs，其5G報告.....
On April 15, 2015, Nokia agreed to acquire Alcatel-Lucent, the Bell Labs' parent company, in a share exchange worth $16.6 billion.[20][21]Their first day of combined operations was January 14, 2016.[22]
-----
5G is looming, but network innovations are needed far more urgently
The path to 5G
16
86
In all the excitement about 5G, it is easy to forget that the most intensive innovations of 2016-2020 will go on in "4.5G" – in Release 13 and 14, of course, but more importantly in the way the carriers and their vendors reinvent their cellular networks with new approaches like virtualization and HetNet, in the desperate bid to keep up with capacity, coverage and efficiency demands.
Nokia’s Bell Labs’ R&D unit published a report this week warning that the capacity of mobile and Wi-Fi networks is not growing nearly quickly enough to satisfy the rise in that demand, especially when it comes to content and video. Of course, such a conclusion, coming from an equipment vendor, is predictable and self-serving, but nonetheless, Bell Labs’ figures are compelling.
Nokia’s Bell Labs’ R&D unit published a report this week warning that the capacity of mobile and Wi-Fi networks is not growing nearly quickly enough to satisfy the rise in that demand, especially when it comes to content and video. Of course, such a conclusion, coming from an equipment vendor, is predictable and self-serving, but nonetheless, Bell Labs’ figures are compelling.
5G is looming, but network innovations are needed far more urgently
The Register - 2 days ago
---
5G (5th generation mobile networks or 5th generation wireless systems) denotes the next major phase of mobile telecommunications standards beyond the current 4G/IMT-Advanced standards. 5G has speeds beyond what the current 4G can offer.
The Next Generation Mobile Networks Alliance defines the following requirements for 5G networks:
- Data rates of tens of megabits per second should be supported for tens of thousands of users
- 1 gigabit per second to be offered simultaneously to many workers on the same office floor
- Several hundreds of thousands of simultaneous connections to be supported for massive sensor deployments
- Spectral efficiency should be significantly enhanced compared to 4G
- Coverage should be improved
- Signalling efficiency should be enhanced
- Latency should be reduced significantly compared to LTE.[1]
The Next Generation Mobile Networks Alliance feels that 5G should be rolled out by 2020 to meet business and consumer demands.[2] In addition to providing simply faster speeds, they predict that 5G networks also will need to meet new use cases, such as the Internet of Things (network equipment in buildings or vehicles for web access) as well as broadcast-like services and lifeline communication in times of natural disaster.
Although updated standards that define capabilities beyond those defined in the current 4G standards are under consideration, those new capabilities have been grouped under the current ITU-T 4G standards.
Contents
[hide]-----
The future of the internet is arriving: you just have to know where to look
2016年4月18日 星期一
New Fanuc Technology Connects Robots to Networks
The technology is meant to enable factory owners to easily customize their robots and systems by downloading any needed applications, much like a consumer downloads smartphone apps on iOS or Android platforms.
New Fanuc Technology Connects Robots to Networks
Rivals will be able to connect their machines and apps to the network
ENLARGEA Fanuc robotic arm operated a faucet at a plant in Bhiwadi, India, on Feb. 16. PHOTO: BLOOMBERG NEWS
By
TAKASHI MOCHIZUKIApril 18, 2016 1:41 a.m. ET
0 COMMENTS
TOKYO—Japanese industrial robot maker Fanuc Corp. said Monday it has developed technology to connect robots to networks that it hopes will give it an edge as it races to build the factory of the future.
The technology is meant to enable factory owners to easily customize their robots and systems by downloading any needed applications, much like a consumer downloads smartphone apps on iOS or Android platforms.
Rival robot makers would eventually be able to connect their machines and apps to the network. Fanuc would also seek revenue from app developers as a platform provider, a model used by Alphabet Inc. and Apple Inc.
The move marks a strategic shift for Fanuc, an industrial powerhouse known for its secretiveness. Chief Executive Yoshiharu Inaba said at a news conference that the initiative reflects a more open approach.
“We believe this will be a de facto standard for factories around the world,” Mr. Inaba said.
Toshimitsu Kawano, managing director of Beckhoff Automation Japan, a German-based automation equipment maker, said “this gives Fanuc a tremendous competitive edge because it would be the first player to provide such a service.”
“Bringing the concept of app stores to the factory robot industry is what U.S. and German companies are all planning for, but haven’t been able to do.”
Fanuc had the biggest share of the global industrial robot market last year with an estimated 17%, according to IHS analyst Jan Zhang.
Fanuc and rivals including General Electric Co., ABB Ltd. and Siemens AG are pushing to develop a default format for connected smart factories, where machines would optimize their own performance using artificial intelligence, an ideal often referred to as Industry 4.0.
Fanuc, which makes robots that assemble Apple’s iPhones and Tesla Motors Inc.’s electric cars, joined forces with Cisco Systems Inc., Rockwell Automation Corp. and Tokyo-based machine-learning startup Preferred Networks Inc. to build its new network platform.
Cisco and Rockwell will provide network expertise including security. Preferred Networks brings expertise in deep-learning, a branch of machine learning.
Japanese Prime Minister Shinzo Abe hopes to leverage artificial intelligence to revive Japan’s economy, but experts say Japanese companies are running behind overseas competitors in research and development, partly due to insufficient collaboration.
Silicon Valley giants such as Alphabet and rising Chinese companies have increased investments in artificial intelligence, especially deep learning. They have snapped up researchers from around the world and have employed enormous data collected through years of providing online services.
The California-based companies have so far used their findings to beef up their online services, such as optimizing Internet searches. They have also begun to use the knowledge to enable autonomous driving.
Write to Takashi Mochizuki at takashi.mochizuki@wsj.com
2016年4月14日 星期四
美國如何監管疫苗 How the United States Regulates Vaccines
美國如何監管疫苗 How the United States Regulates Vaccines
美國的疫苗監管由食品藥品監督管理局（FDA）負責，目前，美國的疫苗供應處於歷史上最安全、最有效的時期。疫苗監管從其步驟看，大致分為試驗、獲得批准、生產、投入使用以及疫苗使用信息反饋等階段。
1，疫苗的研發試驗：醫藥公司按照食品藥品監督管理局的規定，在疫苗動物試驗成功的基礎上，必須對新研發的疫苗進行臨床試驗，試驗共分為三期。第一期（Phase 1）在20至100來名成年志願者中進行，取得成功後進入第二期（Phase 2），人數擴大到數百人；取得成功後再進入第三期（Phase 3） ，人數擴大到上千人。
2，獲得批准：第三期臨床試驗成功後，醫藥公司將結果提交給食品藥品監督管理局，由該局訓練有素的科學家和醫生加以評估，評估的標準十分嚴格，包括疫苗的安全性、有效性以及副作用。食品藥品監督管理局在全面衡量疫苗的有效性、安全性及副作用後，決定批准或不批准新疫苗投入使用。
3，生產：生產疫苗的廠家必須得到食品藥品監督管理局的許可，也就是說食品藥品監督管理局負有監管生產廠家安全生產的責任，在疫苗投入生產後，食品藥品監督管理局會定期檢查生產廠家是否繼續保質生產。
4，投入使用：免疫諮詢委員會（The Advisory Committee on Immunization Practices ，簡稱ACIP）的醫療和公共衛生專家負責仔細審查所有新疫苗的安全性和有效性，並在此基礎上提出使用疫苗的建議，一旦建議經過疾病控制及預防中心（Centers for Disease Control and Prevention）主任的認可並公佈，新疫苗便正式由政府背書，列入官方的兒童免疫計劃（immunization schedule）。
5，疫苗使用信息反饋：疫苗投入市場後，在大規模人群中接種，其使用情況，特別是新發現的不良反應，會通過全國規模的“疫苗不良事件通報系統” （Vaccine Adverse Event Reporting System，簡稱VAERS）反饋給食品藥品監督管理局以及疾病控制及預防中心，並由中心的醫療專家、專業分析人員隨時監控。任何人，包括醫生、生產廠家、疫苗接種者父母或親屬，都可以將所知的疫苗不良事件，特別是副作用報告給“疫苗不良事件通報系統”。
“疫苗不良事件通報系統”的設立，主要目的就是為了收集新疫苗投入使用後發生的不良反應案例，特別是副作用情況，因為在臨床試驗階段，接受試驗的人數畢竟有限，有些疫苗的副作用，可能只有在十萬分之一的人，甚至五十萬分之一的人中才出現；也有一些副作用只會在特定人群中出現，而這些特定人群也許不會出現在臨床試驗的人中。食品藥品監督管理局以及疾病控制及預防中心的醫藥專家、分析人員在收集“疫苗不良事件通報系統”各種反饋數據的基礎上進行研究，如果發現新疫苗的副作用超出臨床試驗的預想並且可能對接種人弊大於利，那麼就會召回疫苗。此外，在疫苗生產階段如果發現有任何不符合規定的情況，也會召回疫苗，比如疫苗標籤缺少規定的說明文字等。
2016年4月13日 星期三
Scientists Can Tell a Good Story
"I remembered how improvisation had helped me in my life, so I started experimenting with scientists in improvisation workshops. And we realized that it was having an immediate effect, and if they did it enough, it had a long-lasting effect."—Alan Alda, actor, director, writer, and science communicator
訂閱：
文章 (Atom)