Scientists Map Miles of Wiring in a Speck of Mouse Brain 在繪製小鼠一立方毫米大腦圖時，科學家收集了 1.6PB 的數據——相當於 22 年不間斷的高清影片

 

科學家繪製出小鼠大腦中數英里長的神經連結圖

在繪製小鼠一立方毫米大腦圖時，科學家收集了 1.6PB 的數據——相當於 22 年不間斷的高清影片。

Scientists Map Miles of Wiring in a Speck of Mouse Brain

In charting a cubic millimeter of a mouse’s brain, scientists amassed 1.6 petabytes of data — the equivalent of 22 years of nonstop high-definition video.

A petabyte (PB) is a unit of measurement in computers and similar electronic devices. One petabyte holds 1000 terabytes (TB) or 1,000,000,000,000,000 bytes.

The Special Relationship Between America and Britain Is a Myth Despite Winston Churchill’s coining. Tibetans get high-altitude edge from extinct Denisovans' genes Britain has landed with a 10% sum on most of its goods exports to America, the lowest rate on offer in tariffs bingo. 西藏人高原基因來自於遠古滅絕人類

Britain has landed with a 10% sum on most of its goods exports to America, the lowest rate on offer in tariffs bingo. But serious pain may still be on its way



Of the relationship between America and the Britain, it’s been said “that the special relationship was special because only one side knew it existed,” writes the journalist Geoffrey Wheatcroft. “Is it too much to hope that the tired and foolish phrase might now be given a rest?"



nytimes.com
Opinion | The Special Relationship Between America and Britain Is a Myth
Despite Winston Churchill’s coining of th

Researchers have known for a while that many people alive today carry genes from human species other than Homo sapiens, the result of ancient interbreeding with Neanderthals and Denisovans. The specifics, though, have not been clear. But in one case they now are, for it is because of these occasional Denisovan ancestors that Tibetans thrive in Tibet http://econ.st/1j0IacI

讚

西藏人高原基因來自於遠古滅絕人類

更新時間 2014年7月3日, 格林尼治標準時間11:47

西藏人的高原基因來自於遠古已滅絕的人類

據《自然》期刊報告，現代人從遠古所繼承的一種基因，可以讓他們適應高原的生活。

據悉，這種遠古的人類已經滅絕。這種叫EPAS-1的基因變種可以影響人類血液中的氧氣，在西藏人當中十分普遍。

西藏人長年生活在海拔4000米的高原。

該DNA(脫氧核糖核酸)的序列與一種早已消失了的遠古人類丹尼索瓦人（Denisovans）的DNA相符合。

其實，包括我們自己在內的現代人類的許多人都攜帶已經滅絕了的遠古人類的DNA。

而這些遠古已滅絕的人類曾經和我們的非洲祖先「雜交」。

40萬年前出現的尼安德特人（the Neanderthals）曾生活在歐洲和西亞地區，直到3萬5千年前。

無論是尼安德特人還是丹尼索瓦人都對現代人的DNA有所貢獻。

而現在，研究人員通過研究血紅蛋白找到了EPAS-1基因與丹尼索瓦人之間的聯繫。

比如，當人體在海拔較高的高原時，體內血液中的氧氣水平就比較低，這時候EPAS-1基因就會告訴身體中的其他的基因活躍起來，包括生產額外的紅血球。

而這種EPAS-1基因的變體在西藏人中十分普遍，這可能和他們在數千年前移居到高原生活時所發生的一種自然的基因選擇。

明確證據

該文章的主要作者之一，加州大學的尼爾森教授說，他們找到了明確的證據這種基因來自丹尼索瓦人。

尼爾森告訴BBC，「如果你、我到海拔高緯度時，我們都將立即會經歷各種不同的不良身體反應。我們會喘氣困難，還可能會得高原病。」

「過一陣，我們的身體為了適應這一情況將會生產更多的紅血球。但是由於我們不適應高原環境，我們的身體可能將會製造許多紅血球。」

「我們的血液變得太粘稠，血壓也會升高，這樣就會有中風的危險，如果是孕婦還可能患妊娠毒血症」。

但西藏人就不會有這些問題，他們的身體不會製造過多的紅血球，因此血液也不會粘稠。

尼爾森教授的研究小組在2010年就發現了西藏人身體中的這種EPAS-1基因變體，但是研究人員當時無法解釋它為什麼與從其他現代人類身上找到的DNA序列不一樣。

因此，他們才從更遠古的人類染色體組序列當中去尋找答案。

研究人員把它同尼安德特人相比較，沒有找到匹配，但當同丹尼索瓦人比較時令人吃驚地找到了吻合。

尼爾森教授解釋說，人類祖先與丹尼索瓦人的「雜交」發生在很久以前。

而當西藏人的祖先移居到高原之後，丹尼索瓦人的DNA在他們的身體中產生了基因變體，並喜歡這種環境轉變。之後它便存在於今天大多數的西藏人身上。

尼爾森教授說，這是人類通過與遠古人類「雜交」後獲得的基因適應新環境的一種清楚和直接的例子。

編譯：凱露

Tibetans get high-altitude edge from extinct Denisovans' genes

The average elevation of Tibet is almost 15,000 feet above sea level. (Goh Chai Hin / AFP/Getty Images)

JULIA ROSEN

Scientific ResearchTibetScience

High in the Himalayas, an ancient gene helps Tibetans thrive at altitude

Denisovans are extinct, but their genes live on in Tibetans

Tibetans provide more proof that early humans mated with Neanderthals and Denisovans

Forget climbing Mt. Everest — for most humans, just eking out a living on the harsh Tibetan plateau is challenge enough. But Tibetan people have thrived there for thousands of years, and a new study says it's thanks to a genetic adaptation they inherited from an ancient human relative.

The study, published Wednesday in the journal Nature, identifies a long segment of DNA shared by the extinct people known as Denisovans and modern-day Tibetans. The segment contains the gene scientists think gives Tibetans a lung up over lowlanders at high altitudes.

Tibetan people possess a unique gene that makes them well-adapted to high-altitude life. This gene appears to have come from an extinct early human relative. (BGI)

No one knew the Denisovans ever roamed the Earth until four years ago, when scientists sequenced the DNA of a finger bone unearthed in a cave in the Altai Mountains of southern Siberia. The genome exhibited similarities to that of modern humans and our extinct Neanderthal relatives, but it was different enough to be considered a distinct species.

Like Neanderthals, Denisovans mated with their human contemporaries, scientists soon discovered. People of Melanesian descent who today inhabit Papua New Guinea share 5% of their genetic makeup with the Denisovans.

Now it appears that Tibetans can also trace part of their ancestry to this mysterious group.

lRelated

OPINION L.A.

Neanderthal DNA shows that man's family tree is decidedly gnarled

SEE ALL RELATED

8

In the new study, scientists collected blood samples from 40 Tibetans and sequenced more than 30,000 nucleotides on a segment of DNA containingEPAS1, the gene that makes Tibetans so well-suited for life at high altitude. Then the scientists compared that sequence with those of 1,000 individuals representing the 26 human populations in the Human Genome Diversity Panel. They found the high-altitude gene in only 2 of the 40 Han Chinese people in the panel and no one else.

“Natural selection by itself could not explain that pattern,” said Rasmus Nielsen, a computational biologist at UC Berkeley and an author of the study. “The DNA sequence was too different from anything else we saw in other populations.”

So they investigated whether the gene might have been imported from extinct Neanderthals or Denisovans, and, bingo, they found a match.

But how did the gene end up in the genome of modern Tibetans? The scientists used computer models to test two different hypotheses. Were Denisovans and Tibetans descended from a common ancestor that gave the gene to both? Or did humans acquire the gene by mating with Denisovans?

Related Story: DNA from Neanderthal toe reveals interbreeding among ancient species

Monte Morin

Early humans and Denisovans probably diverged around half a million years ago, and it’s very unlikely that the gene could be maintained in both populations for so long, Nielsen said.

“By the process of recombination, DNA segments become shorter and shorter and shorter,” he said. “But here we have a very long segment that is shared. That’s very unlikely, statistically.”

Alternatively, the gene could have entered the Tibetan gene pool more recently via sex. Once transferred, the gene would have spread rapidly in the Tibetan population because of the merciless selective pressures of high-altitude living.

“Genetically, Han Chinese and Tibetans are very similar throughout the genome,” Nielsen said. “But for this particular gene, they are extremely differentiated from each other, which is something you only see with very strong or very recent selection.”

cComments

• Iam tibetan and finally what we learn in our school during my days in india really shares similar conclusion. As we tibetan are descendent from cross breed between monkey(a compassionate male) and the female ogress who is relatively voilent in nature.
  SURFMEIN
  AT 3:22 AM JULY 03, 2014

ADD A COMMENTSEE ALL COMMENTS

1

The reason Tibetans need EPAS1 is that their mountainous home — a crease of buckled crust thrust upward by the tectonic collision of India and Asia — lies about 15,000 feet above sea level, on average. Up there, the air contains 40% less oxygen than it does at low elevations.

Although previous studies had identified the importance of EPAS1, scientists still don’t know exactly what the gene does. They know only that it leads to lower levels of hemoglobin — the oxygen-toting protein in blood — in Tibetans who live at high altitude compared with people from low elevations who have acclimatized.

“That may sound counterintuitive,” said Nielsen — after all, wouldn’t you want more oxygen, and thus, more hemoglobin to deliver it? But people without the gene tend “overreact” at altitude.

A gene called EPAS1 helps regulate hemoglobin levels in Tibetans. (BGI)

“As we acclimatize, we’ll start to produce a lot of red blood cells,” he said, speaking for himself and other non-Tibetans. Too many, in fact. “That will expose us to various diseases like hypertension, increased risk of stroke and preeclampsia. There are very negative fitness effects of having too many red blood cells, and the Tibetans avoid them.”

So how do Tibetans get more oxygen? Presumably they don’t, Nielsen said, and scientists are still trying to understand the physiological mechanisms that allow them to cope.

But one thing is now clear: They owe their extraordinary fitness to a rogue gene introduced into the human genome from their long-lost cousins.

Abigail Bigham, an anthropologist at the University of Michigan who was not involved in the study, said now the search for Denisovan DNA should extend to other groups not represented in the Human Genome Diversity Panel.

“When they looked in Han Chinese, they saw it in only two individuals,” Bigham said. “But other populations in Central Asia or East Asia — there are 49 other ethnic minorities in China that have different genetic backgrounds — would have been interesting to look at as well.”

In any case, she said, the new study adds to a growing body of work that has reshaped the way scientists think about human evolution and our relationship to our extinct relatives.

For a long time, most scientists believed Neanderthals and Denisovans had nothing to do with modern humans. Now they realize that these species are responsible for introducing some of the genetic diversity that allowed people to adapt to unique environments.

“We’ve come full circle,” Bigham said. “Not only has there been interbreeding, but in fact that interbreeding has led to important functional changes in the human genome.”

For all things science, follow me @ScienceJulia

How does an EV battery actually work? Are lithium batteries sustainable enough to fulfill the dream of the electric-car revolution?

電動車電池究竟是如何運作的？

鋰電池是否具有足夠的永續性來實現電動車革命的夢想？

作者：Patrick Sisson 檔案頁面

2023 年 2 月 17 日

“”

洛倫佐·佩特蘭托尼

驅動電動車的電池已迅速成為新一代汽車和卡車的最關鍵部件和最昂貴部件。它們不僅代表更清潔的交通運輸的潛力，也代表著地緣政治力量、工業主導地位和環境保護的廣泛轉變。

根據最近的預測，到 2030 年，電動車將占美國新乘用車銷量的一半以上。一項估計表明，全球電池市場的潛在成長可能需要在未來十年內再建造 90 個特斯拉超級工廠規模的設施。

鋰離子電池也用於智慧型手機，為絕大多數電動車提供動力。鋰的反應性非常強，用鋰製成的電池可以保持高電壓和出色的充電能力，從而成為一種高效、密集的能源儲存形式。由於成本下降和性能提升，預計這些電池在可預見的未來仍將在電動車中佔據主導地位。

目前，電動車電池的重量通常約為 1,000 磅，製造成本約為 15,000 美元，其電力足以為普通家庭供電幾天。雖然它們的充電能力會隨著時間的推移而下降，但它們的使用壽命可達 10 到 20 年。

每個電池都是由數百甚至數千個略帶糊狀的鋰離子電化學電池密集排列的集合，通常呈圓柱體或袋狀。每個電池由一個正陰極（通常包含由鎳、錳和鈷製成的金屬氧化物）組成；基於石墨的負極陽極；中間有一種液體溶液，稱為電解質。

這就是鋰的反應性發揮作用的地方；其鬆散的外層電子很容易被分裂掉，留下鋰離子（沒有外層電子的原子）。細胞的基本運作原理就是來回傳遞這些離子和電子。

在充電週期中，透過外部來源引入的電流將電子與陰極中的鋰原子分離。電子繞著外部電路流向陽極（陽極通常由石墨製成，石墨是一種廉價、能量密集且壽命長的、擅長儲存能量的材料），而離子化的鋰原子則通過電解質流向陽極並與電子重新結合。在放電週期中，該過程會逆轉。陽極中的鋰原子再次與電子分離；離子穿過電解質；電子流經外部電路，為電動馬達提供動力。

電動車的擴張導致對製造電池所需礦物的需求龐大。碳酸鋰（用於提取鋰的化合物）的價格在 2010 年至 2020 年間保持相對穩定，但在 2020 年至 2022 年間飆升近 10 倍，刺激了全球新的投資。僅在美國就有十多家電池工廠和眾多潛在的採礦項目正在開發中。

但對原料的追求帶來了巨大的環境、政治和社會成本。

鈷是一種常見的陰極成分，其絕大部分產自剛果民主共和國，該國因童工和強迫勞動而臭名昭著。美國的大部分原料供應都位於部落土地上。作為鋰的主要生產國，智利希望從跨國公司手中奪取生產控制權。與此同時，礦業公司和企業家計劃在海底開採礦物，這可能會破壞脆弱的、不太了解的生態系統（智利正在推動暫停此類海洋採礦）。

電池開發商尋求減少稀有金屬的使用並提高回收率。新創公司和汽車製造商也在競相設計和製造下一代電池，以消除材料難題並提高效率。例如，新一代鋰離子電池已經不再使用鈷。科學家也測試了由更便宜、更豐富的原料製成的鈉硫電池，以及固態電池，顧名思義，固態電池用固態化合物取代液體電解質。它們可能會提供更輕、更穩定、充電更快的替代品。

預測顯示，只需幾年時間，電動車的價格就將與內燃機汽車持平，加速普及。專家預測，隨著各國和各企業競相爭奪該行業十幾個主導企業中的地位，電池製造業將出現迅速擴張、整合和試驗。離子在電池陰極和陽極之間的微小旅程很可能成為未來十年最重要的旅程之一。

作者：Patrick Sisson

How does an EV battery actually work?

Are lithium batteries sustainable enough to fulfill the dream of the electric-car revolution?

By Patrick Sissonarchive page

February 17, 2023

""

Lorenzo Petrantoni

The batteries propelling electric vehicles have quickly become the most crucial component, and expense, for a new generation of cars and trucks. They represent not only the potential for cleaner transportation but also broad shifts in geopolitical power, industrial dominance, and environmental protection. 

According to recent predictions, EVs will make up just over half of new passenger car sales in the US by 2030. One estimate suggests that the potential growth of the global battery market could require 90 more facilities the size of the Tesla Gigafactory to be built over the next decade.

Lithium-ion batteries, also found in smartphones, power the vast majority of electric vehicles. Lithium is very reactive, and batteries made with it can hold high voltage and exceptional charge, making for an efficient, dense form of energy storage. These batteries are expected to remain dominant in EVs for the foreseeable future thanks to plunging costs and improvements in performance. 

Right now, electric-car batteries typically weigh around 1,000 pounds, cost around $15,000 to manufacture, and have enough power to run a typical home for a few days. While their charging capacity degrades over time, they should last 10 to 20 years.

Each battery is a densely packed collection of hundreds, even thousands, of slightly mushy lithium-ion electrochemical cells, usually shaped like cylinders or pouches. Each cell consists of a positive cathode (which typically contains metal oxides made from nickel, manganese, and cobalt); a negative, graphite-­based anode; and a liquid solution in the middle, called an electrolyte. 

This is where lithium’s reactivity comes into play; its loosely held outer electron can easily be split off, leaving a lithium ion (the atom sans its outer electron). The cell basically works by ping-ponging these ions and electrons back and forth. 

During the charging cycle, an electric current introduced via an external source separates the electrons from the lithium atoms in the cathode. The electrons flow around an outside circuit to the anode—which is typically composed of graphite, a cheap, energy-dense, and long-lasting material that excels at storing energy—while the ionized lithium atoms flow to the anode through the electrolyte and are reunited with their electrons. During discharge cycles, the process reverses. Lithium atoms in the anode get separated from their electrons again; the ions pass through the electrolyte; and the electrons flow through the outside circuit, which powers the motor. 

EV expansion has created voracious demand for the minerals required to make batteries. The price of lithium carbonate, the compound from which lithium is extracted, stayed relatively steady between 2010 and 2020 but shot up nearly tenfold between 2020 and 2022, spurring new investments across the globe. More than a dozen battery plants and numerous potential mining projects are in development in the US alone. 

But the quest for raw materials comes with extensive environmental, political, and social costs. 

The vast majority of cobalt, a common cathode component, comes from the Democratic Republic of the Congo, infamous for child and forced labor. Much of the US supply of raw materials is on tribal lands. Chile, a key producer of lithium, wants to wrest control of production from multinationals. Meanwhile, mining companies and entrepreneurs have plans to mine the seabed for minerals, which could damage a fragile, poorly understood ecosystem (Chile is pushing a moratorium on such ocean mining). 

Battery developers seek to cut back on the use of rare metals and improve recycling. Startups and automakers are also racing to design and build next-generation batteries that eliminate material challenges and boost efficiency. A new generation of lithium-ion batteries has already eliminated the use of cobalt, for instance. Scientists have also tested sodium-sulfur batteries, made from much cheaper and more abundant raw materials, and solid-state batteries, which—as the name implies—replace the liquid electrolyte with solid compounds. They may offer a lighter, more stable, faster-charging alternative.

Forecasts suggest that EVs will achieve price parity with cars based on internal-combustion engines in just a few years, accelerating adoption. And experts predict rapid expansion, consolidation, and experimentation in battery manufacturing as countries and companies race for a position among the sector’s dozen or so dominant players. The tiny trip ions take between the cathodes and anodes of battery cells will likely become one of the most important journeys of the next decade. 

hide

by Patrick Sisson

----

 The World Turned Upside Down is a sculpture by the Turner Prize-winning artist Mark Wallinger, on Sheffield Street, London, within the campus of the London School of Economics. The name World Turned Upside Down comes from a 17th-century English ballad.^[1] The sculpture, measuring 13 feet (4 m) in diameter, features a globe resting on its North Pole and was unveiled in March 2019. It reportedly cost over £200,000,^[2] which was funded by alumni donations.

Disputed content

[edit]

The artwork attracted controversy for showing the island of Taiwan as a sovereign entity, rather than as part of the People’s Republic of China.^[3] After dueling protests^[4][5] by students from both the PRC and ROC and reactions by third party observers (which included the President of Taiwan,^[6] Taiwanese Ministry of Foreign Affairs^[7] and the co-chairs of the British-Taiwanese All-Party Parliamentary Group in the House of Commons^[8]) the university decided later that year (2019) that it would retain the original design which chromatically displayed the PRC and ROC as different entities but with the addition of an asterisk beside the name of Taiwan and a corresponding placard that clarified the institution's position regarding the controversy.^{[9][10][11][12]}

A group of students repeatedly vandalised the globe for its omission of the state of Palestine, a non-member observer state in the United Nations. The globe features Jerusalem marked as the capital of Israel, instead of the internationally recognised capital of Tel-Aviv (including by the UK).^[13]