20171123

Plague reached Europe by Stone Age
Plague was present in Europe during the late Stone Age, according to a study of ancient remains.
Writing in Current Biology journal, researchers suggest the deadly bacterium entered Europe with a mass migration of people from further east.
They screened more than 500 ancient skeletal samples and recovered the full genomes of plague bacteria from six individuals.
These six variously date to between Late Neolithic and Bronze Age times.
Neolithic【名】新石器時代◆およそ紀元前8000年～5000年の間の、定住して農業を行い、磨製石器や武器の使用が始まった時代。
Bronze Age 《the ～》《考古》青銅器時代
The plague-positive samples come from Russia, Germany, Lithuania, Estonia and Croatia.
"The two samples from Russia and Croatia are among the oldest plague-positive samples published. They are contemporary with [a] previously published sample from the Altai region [in Siberia]," co-author Alexander Herbig from the Max Planck Institute for the Science of Human History in Jena, Germany, told BBC News.
 contemporary【形】  同時期に起こる［存在する］、同時代に存在した
The plague bacterium, Yersinia pestis, was responsible for several major historic pandemics, including the infamous Black Death in the 14th Century, which is estimated to have killed between 30% and 60% of Europe's population.
Analysis of the ancient plague DNA shows that Y. pestis genomes from the Neolithic and Bronze Age were all fairly closely related.
This is intriguing because the individuals from which they were recovered come from such a wide geographic area.
intriguing 【形】興味［好奇心］をそそる［かき立てる］、興味ある
"This suggests that the plague either entered Europe multiple times during this period from the same reservoir, or entered once in the Stone Age and remained there," said co-author Aida Andrades Valtuena, also from the Max Planck Institute in Jena.
In order to clarify which scenario was most likely, the researchers looked for clues from archaeology and from the analysis of ancient human DNA.
From about 4,800 years ago, there was a major expansion of people into Europe from a region called the Caspian-Pontic Steppe in present-day Russia and Ukraine.
ポントス・カスピ海草原
These people carried a distinctive genetic component - also seen in Siberians and Native Americans - that had not been present in Europeans before the late Neolithic.
The earliest indications of plague in Europe coincide with the arrival of this "steppe ancestry" in Europeans.
Dr Herbig said this supports "the view that Y. pestis was possibly introduced to Europe from the steppe around 4,800 years ago, where it established a local reservoir before moving back towards Central Eurasia".
Analysis shows that plague bacteria genes related to virulence were changing at this time. But further work is needed to determine how these changes affected the severity of the disease. 
However, it's certainly possible that these early Y. pestis bacteria were already capable of causing large-scale epidemics.
The steppe people could have been moving to get away from a plague outbreak - although the effects of climate change on the landscape in this region may also have played a role.
The disease could also have been involved in profound genetic changes seen in European populations at this time. In some regions, the steppe people appear to have largely replaced the previous Neolithic inhabitants. 
"It's possible that certain European populations, or the steppe people, may have had a different level of immunity [to Y. pestis]," said Johannes Krause, from the Max Planck Institute. 
Dr Herbig commented: "The plague might have been a factor among others that promoted the migration processes during this time period. However, our current data has insufficient resolution to see how specific regions within Europe were affected differently by the disease."   
He added that the team planned to screen more skeletal material from all over Europe as a next step.

20171122

Mosquito-spreading drone to fight diseases
Drones that scatter swarms of sterile mosquitoes over wide areas are being developed to help stop the spread of diseases such as malaria.
無精子症【形】不妊の、子を生まない、無精子の ステライル
Sterile male mosquitoes cannot produce offspring when they mate with females. By crowding out other males, they reduce the mosquito population.
crowd out 【句動】〔狭い場所から～を〕押しのける、押し出す、締め出す
But spreading them is difficult in areas without roads, so technology organisation WeRobotics has been developing drones to do the job.It will trial the idea in 2018.
"Mosquitoes carry many diseases such as malaria, dengue fever and Zika virus. It makes them one of the biggest animal killers worldwide," Adam Klaptocz, WeRobotics co-founder, told the BBC.
"There are lots of methods to control mosquito populations - fumigation, insecticide - but they all have downsides. Insecticide is not good for environment and needs to be constantly deployed."
fumigation 【名】 薫蒸消毒、燻蒸   f?m(us) smoke
downside【名】否定的側面、不都合な点
Releasing sterile insects had been an effective method of population control for a variety of species, he said.
Often the sterile insects are released from backpacks carried by the scientists, but it is difficult to spread them over a wide area - and they cannot simply be dumped in one location.
WeRobotics was approached by international aid organisations to help produce a solution.
"A lot of the places where these diseases exist are also places where roads do not exist. The drones could spread the mosquitoes where there are no roads," said Mr Klaptocz.
But one of the challenges is packing hundreds of thousands of fragile mosquitoes into a payload without damaging their thin legs and wings. 
"A mosquito that comes out of a drone damaged - or dead - is not going to mate with females," said Mr Klaptocz.
To protect the insects, they are first cooled to 4-8C, putting them into a sleep-like state that stops them moving around. The next challenge is releasing the insects gradually over a wide area, without waking the whole lot up at once.
whole lot  《a ～》全部
To do so, the team has designed a rotating platform with holes in, through which individual mosquitoes fall. They land in a holding chamber where they wake up, and can fly out into the wild.
"Community engagement is also a key part of the release campaign," Mr Klaptocz told the BBC.
"We may be spreading mosquitoes in areas where they are seen as a vector of death. We need to speak to the local population before a single mosquito is released." 
The drones are still in development, but the non-profit company hopes to trial its technology in Latin America in 2018.

20171121

Albatrosses hit by fishing and climate
The spectacular wandering albatrosses in Sunday's Blue Planet programme on the BBC have suffered a major decline in numbers over the past three decades.
wandering albatross 《鳥》ワタリアホウドリ
New research suggests breeding pairs of this species are now little more than half what they were in the 1980s.
Scientists say the losses are the result of careless fishing practices and climate pressures.
The researchers are affiliated to the British Antarctic Survey (BAS), which organised the filming for the TV show.
affiliate【他動】〔人や団体を〕会員［仲間・支部］にする、傘下に置く
BAS has been running a long-term tagging and monitoring study on Bird Island, a 4km-long stretch of land on the western fringes of South Georgia in the South Atlantic.
サウスジョージア・サウスサンドウィッチ諸島は、南大西洋にあるイギリス領の諸島。フォークランド諸島の約1,000km東（南緯54度30分、西経37度）にある。
The animals' global population is spread across only a handful of sub-Antarctic territories,
The wandering albatrosses are not the only species, though, to experience a slump.
spread across ～に散在する
Black-browed and grey-headed albatrosses have followed a similar trend.
"These populations have all declined over the period we've been monitoring them," said BAS expert Richard Phillips."There have been different phases, so for the wandering albatrosses there was a gradual decline and then it got really steep before things slowed up. Some of the variability is down to a changing environment; some of it is down to fishing effort."
down to《be ～》（人）に依存して［頼って］いる
Albatrosses will often try to take the bait on longline fishing gear. They get snagged on the hooks, are pulled under the water and are drowned.
snag【他動】 〔船・釣り糸などを沈み木に〕引っ掛ける
In the immediate vicinity of South Georgia, toothfish trawlers have modified the way they put their lines out to limit this collateral damage, but the birds forage over thousands of square km and will often encounter vessels that still do not use the most sensitive fishing methods.
Patagonian toothfish《魚》マゼランアイナメ
forage 【自動】〔食糧を〕あさる、探し回る
And sometimes, shifts in climate can drive the birds towards this danger, says BAS colleague Dr Deborah Pardo.
"We also found the grey-headed albatross population was particularly affected by the climatic event of El Nino, which coincided with increased fishing activity in their foraging areas.
"El Nino reduced the amount of food available so the birds probably switched to feeding on discards behind fishing vessels, increasing the number being hooked on longlines."
Not all climate effects are negative. The recent increasing trend towards stronger poleward winds actually benefits the wandering albatrosses. 
"Such winds make their flight more efficient," Dr Phillips told BBC News. "They can fly faster. Essentially, these winds make the cost of travel cheaper for them."  
Sunday's programme considered the breeding outcomes for elderly pairs of wandering albatrosses.
Separate BAS research has established that the very last chicks these senior albatrosses produce will often succeed and flourish.
Dr Phillips explained: "There's a theoretical prediction that if a bird is about to die then it might put more effort into rearing the last chick, or the alternative is the very fact that it has reared that chick has a cost - there's a cost of reproduction - and subsequently the bird won't recover and it will die for that reason."  
Currently on Bird Island there are roughly 700 pairs of wandering albatross, 3,000 pairs of grey-headed albatross and 7,000 pairs of black-browed albatross. They longterm study detailing the falls in population is published in the journal Proceedings of the National Academy of Sciences.

20171119

Apple delays launch of smart speaker
Apple is delaying the release of its HomePod smart speaker until 2018.
The electronics giant said the device, which was due to be released in December this year, still needed development work.It said the HomePod would be ready to go on shop shelves in the US, UK and Australia "early in 2018". The news is a blow to its plans to take on rivals Amazon and Google in the growing market for home devices that use AI to help consumers.
'Not surprising'
In a statement sent to news organisations, Apple said the wireless speaker needed "a little more time before it's ready for our customers".
The delay will mean Apple misses the lucrative holiday season during which many consumers buy gadgets as gifts.
The gadget was first unveiled in June this year when Apple said it would go on sale in the US for $349 (￡265). In the UK it was expected to cost ￡350. 
It was designed to be a competitor to other smart speakers - such as Amazon's Echo and Google's Assistant. Sonos, Microsoft and others also make similar gadgets.Like them it was designed to play music and act as a hands-free helper letting owners set timers, maintain shopping lists and get reports about the news, weather and other subjects.Since Apple unveiled the HomePod both Google and Amazon have added new models to their ranges of smart speakers, intensifying the competition with Apple.
Writing in Engadget, associate editor Jon Fingle said the delay was "not surprising" given that the HomePod was Apple's first try at a smart speaker. "The HomePod isn't necessarily in trouble," he said. "but it may face a tougher battle than it did beforehand."

20171118

First gene-editing in human body attempt
Gene-editing has been attempted on cells inside a patient, in a world first by doctors in California.
Brian Madeux, 44 from Arizona, was given the experimental treatment to try to correct a defect in his DNA that causes Hunter's syndrome.
Hunter症候群とは
Hunter症候群はムコ多糖症Ⅱ型であり、ムコ多糖分解酵素活性の欠損または低下によって､結合織を中心とした全身の諸臓器に不完全に分解されたムコ多糖が蓄積することにより､様々な症状を呈する遺伝性代謝異常症です。
Mr Madeux says he was prepared to take part in the trial as he is "in pain every second of the day".
It is too soon to know whether or not the gene-editing has worked in Mr Madeux's case.
Hunter's syndrome is rare. Patients are born without the genetic instructions for an enzyme that breaks down long sugary molecules called mucopolysaccharides.
mucopolysaccharide 【名】ムコ多糖（体）
Instead, they build up in the body and damage the brain and other organs. Severe cases are often fatal. 
"I actually thought I wouldn't live past my early 20s," said Mr Madeux.
Patients need regular enzyme replacement therapy to break down the mucopolysaccharides. 
But Mr Madeux has been given an experimental treatment to rewrite his DNA to give him the instructions for making the enzyme.The therapy was infused into his bloodstream on Monday at Oakland's UCSF Benioff Children's Hospital.
The therapy contains two molecular scissors - called zinc finger nucleases - that cut the DNA at a precise spot.
ジンクフィンガーヌクレアーゼ (Zinc Finger Nucleases, ZFNs) はジンクフィンガードメインとDNA切断ドメインから成る人工制限酵素である。ジンクフィンガードメインは任意のDNA塩基配列を認識するように改変可能で、これによってジンクフィンガーヌクレアーゼが複雑なゲノム中の単一の配列を標的とすることが可能となる。亜鉛フィンガー
This creates an opening for a new piece of DNA, containing the desired instructions, to be inserted into the patient's genetic code. The genetic therapy has been designed so it becomes active only once it gets inside Mr Madeux's liver cells. Dr Chester Whitley, one of the doctors working on the trial, told the BBC: "If works as well as it does in mice, this has huge ramifications.
ramification 【名】予期しない結果［問題・影響］枝分かれすること、分岐
"I'm very optimistic we have a both safe and efficacious way of providing gene therapy."
efficacious 【形】  〔薬剤・治療などが〕効果のある
His long-term hope is to perform gene-editing shortly after birth, because an "untreated baby loses 20 IQ points per year".  
Gene editing has been tried in people before, but cells have been taken out of the body, edited, checked for errors and then placed back in.  
That works for tissues that can be temporally removed and returned at a later date like a sample of bone marrow.
However, such an approach is impossible for organs like the liver, heart or brain. It is why doctors have attempted the gene editing inside the patient's body.
The trial is testing only the safety of performing the gene editing and it will require more research to know if it could be a valid therapy.
So far there have been no side effects in Mr Madeux and if everything continues to go well, then up to nine patients will receive the experimental procedure as part of the study.  
'New frontier'
Dr Sandy Macrae, from Sangamo Therapeutics, which designed the therapy, said: "For the first time, a patient has received a therapy intended to precisely edit the DNA of cells directly inside the body.
"We are at the start of a new frontier of genomic medicine." 
Further safety trials using the same technology to treat haemophilia B and Hurler syndrome are also planned.
hemophilia B B型血友病、クリスマス病◆クリスマス因子という血液凝固因子のIX型因子が欠損している病気
Hurler症候群とは
Hurler症候群はムコ多糖症Ⅰ型であり、ムコ多糖分解酵素活性の欠損または低下によって､結合織を中心とした全身の諸臓器に不完全に分解されたムコ多糖（GAG：グルコサミノグリカン）が全身に蓄積することにより､様々な症状を呈する常染色体劣性遺伝疾患です。出生男児の約39万人に1人発症すると報告されています。
Mr Madeux says he is prepared to have his DNA altered "if it will prolong my life and help scientists find cures for humankind".

20171115

Sex unlikely to cause cardiac arrest, study finds
Sudden cardiac arrest is associated with sexual activity far more often in men than women, research suggests.
cardiac arrest 心（臓）停止、心拍停止、心不全
But sex is a rare trigger for sudden cardiac arrest.
Only 34 out of the 4,557 cardiac arrests examined occurred during or within one hour of sexual intercourse and 32 of those affected were men.
Sumeet Chugh, of the Cedars-Sinai Heart Institute, said his study is the first to evaluate sexual activity as a potential trigger of cardiac arrest.
The research was presented at a meeting of the American Heart Association.
A cardiac arrest happens when the heart malfunctions and suddenly stops beating. It causes someone to fall unconscious and stop breathing and unless treated with CPR, it is fatal.
This differs from a heart attack, where blood flow to the heart is blocked.
heart attack 心臓まひ［発作］、心発作
It is known that sexual activity can trigger heart attacks, but the link with cardiac arrest was previously unknown. 
Dr Chugh and his colleagues in California examined hospital records on cases of cardiac arrest in adults between 2002 and 2015 in Portland, Oregon.
Sexual activity was associated in fewer than 1% of the cases. The vast majority were male and were more likely to be middle-aged, African-American and have a history of cardiovascular disease. 
The study also found CPR was performed in only one-third of the cases, despite them being witnessed by a partner.
cardiovascular【形】 心臓血管の
Dr Chugh said: "These findings highlight the importance of continued efforts to educate the public on the importance of bystander CPR for sudden cardiac arrest, irrespective of the circumstance."
irrespective【形】 ～に関わりない
He said it shows the need for people to be educated about how to administer CPR. 
Another study presented at the conference showed children as young as six can learn it.
After a heart attack or surgery, the British Heart Foundation suggests patients should typically wait four to six weeks before resuming sexual activity.

20171114

'Urgent need' for football header research
Scientists investigating links between heading footballs and dementia say there is an urgent need for more research.
It follows the screening of a BBC documentary "Dementia, football and me", featuring Alan Shearer.
Last year, scientists at Stirling University found just one session of heading a ball could lead to an immediate decrease in brain function. 
They said more work was needed to assess long-term effects. 
The academics have called for funding for further studies looking at the risks of heading footballs. 
The BBC documentary, which was screened on Sunday night, heard from current and retired professional footballers, the relatives of former players diagnosed with dementia, the Football Association (FA), the Professional Footballers' Association (PFA) and scientists in sports medicine.
Many of those interviewed raised concerns that there could be a link between heading the ball and brain health but said that more research was required.
The documentary included footage of former England international Shearer undergoing tests in a lab at Stirling, where academics have, for the first time, found direct evidence of brain changes immediately after heading a ball.
The FA and PFA have commissioned research into whether the degenerative neurocognitive disease is more common in ex-professional footballers than the rest of the population.
neurocognitive 【形】 神経認知の
But cognitive neuroscientist Dr Magdalena Ietswaart and Dr Angus Hunter, reader in exercise physiology, said more funding was needed for scientific studies that would provide understanding of the risks associated with heading footballs.
'Definitive answers'
Dr Ietswaart said: "We do not yet know whether there is a definitive link between football and dementia. This can only be discovered by carrying out research in this area.
"Scientific developments open up a new approach that is achievable but requires a robust funding drive. If you want real answers, you need to understand what is happening in the brain; what is cause and effect, the approach we use here at Stirling.
"Until now, we did not have sensitive or direct ways to identify how moving a ball with your head can impact brain health. 
"However, we now have stronger neuroscience emerging that can look directly at what goes on in the brain as a result of heading the ball."
She added: "We have applied these techniques here at Stirling but there is a lot more that we, and others, can do to give definitive answers on the dangers of heading. 
"Current neuroscience has substantial promise in providing the evidence-base on the effects playing football has on brain health that is currently lacking." 
The tests undertaken by Shearer showed immediate brain changes after heading the ball - the same changes observed in participants who took part in the landmark study. 
The research, published in EBioMedicine, is the first to show direct evidence for short-term sub-concussive changes in the brain following any sport-related impact.
concussive 【形】  《医》震とう性の
After meeting the Stirling team, Shearer said: "Football should be encouraging these universities to do as much research as possible but, like everything else, these universities need funding.
"There's enough money around nowadays in football but not enough of it is being given to research. It is about time we had more definitive answers." 
Dr Hunter said: "As conveyed by the BBC documentary, our study is the first to show changes in brain function after heading the ball.
"Combined with the anecdotal evidence, our research and this documentary should provide the stimulus for further scientific research to be carried out in this area."
anecdotal evidence【名】  事例証拠
The research was funded by the National Institute of Health Research.
 

20171112

Delhi residents panic as 'deadly smog' returns
Panic has gripped the Indian capital, Delhi, as residents woke up to a blanket of thick grey smog on Tuesday.
Visibility is poor as pollution levels reached 30 times the World Health Organization's recommended limit in some areas.The Indian Medical Association (IMA) declared "a state of medical emergency" and urged the government to "make every possible effort to curb this menace".
menace【名】 脅威となる［害を及ぼす］もの
People have been posting dramatic pictures on social media showing the extent of the problem.
The levels of tiny particulate matter (known as PM 2.5) that enter deep into the lungs reached as high as 700 micrograms per cubic metre in some areas on Tuesday, data from the System of Air Quality Weather Forecasting and Research website shows.The IMA has also recommended that the city's half marathon, due to be held on 19 November, should be cancelled.Most social media users have complained of breathing difficulties.
Delhi sees pollution levels soar in winter due to farmers in neighbouring Punjab and Haryana states burning stubble to clear their fields.
stubble【名】刈り株
Activists say very little has been done to stop the practice despite Delhi facing severe pollution for a number of years.Low wind speeds, dust from construction sites, rubbish burning in the capital and firecrackers used in festivals also contribute to increasing pollution levels.
The government enacted a plan in October to combat some of these problems. 
The plan includes traffic restrictions and the shutdown of a major power plant. Last year car rationing was trialled in an attempt to curb pollution. 
But none of the measures seem to have had much impact.
Some Twitter users believe that the problem needs a long-term solution instead of a "piecemeal approach".
piecemeal【形】段階的な、部分的な◆物が作られたり、物事が達成されたりするときのさま。
【副】少しずつ、漸次に断片的に、ばらばらに

20171111

Scale of 'nitrate timebomb' revealed
Huge quantities of nitrate chemicals from farm fertilisers are polluting the rocks beneath our feet, a study says.
Researchers at the British Geological Survey say it could have severe global-scale consequences for rivers, water supplies, human health and the economy.
They say the nitrate will be released from the rocks into rivers via springs.
That will cause toxic algal blooms and fish deaths, and will cost industry and consumers billions of pounds a year in extra water treatment.
In a paper in Nature Communications, the scientists from BGS and Lancaster University estimate that up to 180 million tonnes of nitrate are stored in rocks worldwide - perhaps twice the amount stored in soils.
They say this is the first global estimate of the amount of nitrate trapped between the soil layer and the water-bearing aquifers below. They warn that over time the nitrate will inevitably slowly seep into the aquifers.
aquifer【名】《地学》帯水層
Most nitrate, the team says, is in rocks in North America, China and Europe where fertiliser has been lavishly applied for decades.
In some developed countries, the amount of nitrate stored in the rocks is increasing, despite improvements in farming practice and the introduction of rules to control the pollutant.
In developing countries, the problem is currently not so severe. But there is an urgent need for early intervention to avoid the environmental damage experienced by rich countries.
Matthew Ascott, hydrogeologist at the BGS and lead author, said: "With big investments being made to reduce water pollution through changes in farming, it is vital that we understand what pollution is already in the environment.
hydrogeologist水文地質学
"Water and the pollutant travels through the rocks below our feet very slowly. This and a history of intensive agriculture means that a large store of nitrate pollution has built up over time. 
"When this pollution is released, it will continue to impact water quality for decades, in some cases, even where controls on fertiliser use have been put in place."
This is what's known as the nitrate timebomb.
The EU is trying to clamp down on careless application of nitrates but farmers say the fertilisers are vital for agricultural productivity.
The UK government has said all EU environmental laws will be brought into British law after Brexit. But a legal taskforce set up by the UK Environmental Law Association (UKELA) to examine the risks of Brexit identified nitrate pollution as an example of the protections that will be at risk when European laws are rolled over into domestic legislation in 2019.

20171110

Breast cancer 'can return 15 years after treatment ends'
Breast cancer can resurface after remaining dormant for 15 years following successful treatment, a study has found. Women with large tumours and cancer that had spread to the lymph nodes had the highest 40% risk of it coming back.Researchers writing in the New England Journal of Medicine said extending treatment with hormone therapy could reduce the risk of it recurring.Scientists analysed the progress of 63,000 women for 20 years.
All had the most common form of breast cancer.
This is a type fuelled by the hormone oestrogen which can stimulate cancer cells to grow and divide.
estrogen 【名】《生化学》エストロゲン、女性ホルモン物質、発情ホルモン物質
Every patient received treatments such as tamoxifen or aromatase inhibitors which block the effects of oestrogen or shut off the hormone's supply.
tamoxifen【名】 タモキシフェン◆がんの治療に用いる薬
aromatase inhibitor  アロマターゼ阻害薬［剤］閉経前の女性では、エストロゲンはおもに卵巣で合成されますが、閉経後は卵巣機能が低下するために、アロマターゼという酵素によって男性ホルモン（アンドロゲン）から転換されて合成されます。
アロマターゼ阻害薬は、アロマターゼの働きを抑えることでエストロゲンの合成を阻害する薬で、その作用メカニズムの違いよって（1）アロマターゼと結合することでその働きを妨げるタイプ、（2）アロマターゼの働きを完全に不活性化するタイプの2種類に分類することができます。
Although after five years of treatment their cancers had gone, over the next 15 years a steady number of women found that their cancer spread throughout their body - some up to 20 years after diagnosis. 
Women who originally had large tumours and cancer that had spread to four or more lymph nodes were at highest risk of the cancer returning the next 15 years, the study said. 
Women with small, low-grade cancers and no spread to the lymph nodes had a much lower 10% risk of cancer spread over that time.
'Remarkable'
Lead researcher Dr Hongchao Pan, from University of Oxford, said: "It is remarkable that breast cancer can remain dormant for so long and then spread many years later, with this risk remaining the same year after year and still strongly related to the size of the original cancer and whether it had spread to the (lymph) nodes."  
Doctors have long known that five years of tamoxifen reduces the risk of recurrence by about a third in the five years after stopping treatment.Recent research has suggested that extending hormone therapy to 10 years may be more effective at preventing breast cancer recurrence and death.
Aromatase inhibitors, which only work for post-menopausal women, are believed to be even more effective. 
But there are side effects with hormone treatments which can affect patients' quality of life and cause them to stop taking the pills. 
These include menopausal symptoms, osteporosis, joint pain and carpal tunnel syndrome.
carpal-tunnel syndrome
手根管症候群   正中神経は手首部にある手根管という狭いトンネルを通り抜ける構造になっており、周囲三方向を骨の壁、残りの一方は強靭な 靭帯じんたいによって囲まれています。そのため、この部分で正中神経が圧迫されやすい構造になっており、手の使いすぎによる 腱鞘炎けんしょうえん、妊娠時の水分貯留、糖尿病、 甲状腺機能低下症やアミロイドーシスなどにより容易に正中神経が損われて正中神経麻痺を起こします。これを手根管症候群といいます。
Prof Arnie Purushotham, senior clinical adviser at Cancer Research UK, which funded the study, said that since the research began, new drugs had been used to treat breast cancer and those worked in different ways to tamoxifen.
He said: "It's vital that work continues to better predict which cancers might return.
"We also need to know what the difference for women might be in taking hormone therapies for 10 years instead of five, the side effects and how this affects patients' quality of life."
Sally Greenbook, from charity Breast Cancer Now, said it was essential that women discussed any changes in treatment with their doctor.
"We would urge all women who have had treatment for breast cancer not to be alarmed, but to ensure they are aware of the signs of recurrence and of metastatic breast cancer, and to speak to their GP or breast care team if they have any concerns."

20171109

Fossil of 'our earliest ancestors' found in Dorset
Fossils of the oldest-known ancestors of most living mammals, including human beings, have been unearthed in southern England. Teeth belonging to the extinct shrew-like creatures, which scampered at the feet of dinosaurs, were discovered in cliffs on the Dorset coast.
scamper【自動】〔ふざけてまたは急いで〕走る、動く
Scientists who identified the specimens say they are the earliest undisputed fossils of mammals belonging to the line that led to humans. They date back 145 million years.
''Here we have discovered from the Jurassic coast a couple of shrew-like things that are to date unequivocally our earliest ancestors,'' said Dr Steve Sweetman of Portsmouth University, who examined the ancient teeth.
to date 今まで
The mammals were tiny, furry creatures that probably emerged under the cover of night.
One, a possible burrower, dined on insects, while the larger may have eaten plants as well.
burrower 【名】 穴を掘る動物、穴居性［穴にすむ］動物
Their teeth were highly advanced, of a type that can pierce, cut and crush food.
pierce  【他動】～に穴を開ける
''They are also very worn which suggests the animals to which they belonged lived to a good age for their species,'' said Dr Sweetman.
live to a good age 長生きする
''No mean feat when you're sharing your habitat with predatory dinosaurs."
no mean feat for《be ～》～にしては見事［立派］なものである
feat 【名】 〔勇気ある〕手柄、功績〔技能や想像力などに優れた〕妙技、業績
mean【形】劣った
The fossils were discovered by Grant Smith, then an undergraduate student. He was sifting through rock samples collected at Durlston Bay near Swanage for his dissertation when he found teeth of a type never before seen in rocks of this age.
sift through～をより分ける、～をふるいにかける、取捨選択する
dissertation 【名】（学位）論文、〔文章・口頭による〕形式の整った論述ResearchersImage copyrightSTEVE SWEETMAN
''The Jurassic Coast is always unveiling fresh secrets and I'd like to think that similar discoveries will continue to be made right on our doorstep," said Prof Dave Martill of Portsmouth University, who supervised the project.
One of the new species has been named Durlstotherium newmani after Charlie Newman, who is the landlord of a pub close to where the fossils were discovered, and is also a keen fossil collector.
The second has been named Dulstodon ensomi, after Paul Ensom, a local palaeontologist. 
The findings, published in the Journal, Acta Palaeontologica Polonica, add new evidence to a hotly-debated field.
Recent fossil discoveries from China pushed back the date of the earliest mammals to 160 million years ago. 
However, this has been disputed, based on data from molecular studies. 
A separate study revealed this week suggests that the earliest mammals were night creatures that only switched to daytime living after the demise of the dinosaurs.
The research, published in the journal, Nature Ecology and Evolution, could explain why many mammals living today are nocturnal.

20171108

Malaria breath test shows promise
People with malaria give off a distinctive "breath-print" that could be used as a test for the disease, according to American scientists.They had already tried out a crude prototype breathalyser in Africa, a tropical medicine conference heard. The test was reasonably good at detecting cases in children, but needs developing to become a routine device.
One of the odours it sniffs out is identical to a natural smell that attracts insects that spread malaria.
Pine trees and conifers emit these terpenes to summon mosquitoes and other pollinating insects, say the researchers, from Washington University in St Louis.
conifer 【名】針葉樹、球果植物
terpene【名】《化学》テルペン   イソプレンを構成単位とする炭化水素で、植物や昆虫、菌類などによって作り出される生体物質である
They believe people with malaria who have this odour in their breath may also attract mosquitoes and infect more of the biting insects, which can then spread the disease to other people that they bite.
Although the test needs perfecting, it could offer a new cheap and easy way to help diagnose malaria, Prof Audrey Odom John and colleagues say.
Distinct odour
The prototype breath test detects six different odours or volatile organic compounds to spot cases of malaria.
The researchers tried it on breath samples from 35 feverish children in Malawi, some with and some without malaria.
It gave an accurate result in 29 of the children, meaning it had a success rate of 83%. 
This is still too low for the test to be used routinely, but the researchers hope they can improve its reliability and develop it into an off-the-shelf product.
Simple, rapid blood tests for malaria are already available, but they have limits, say the Washington University researchers.
Testing blood can be expensive and technically challenging in rural settings.
A non-invasive method of detection that does not require blood samples or technical expertise could be of great benefit. Prof James Logan from the London School of Hygiene and Tropical Medicine said: "The rapid detection of asymptomatic malaria is a challenge for malaria control and will be essential as we move towards achieving the goal of malaria elimination. A new diagnostic tool, based on the detection of volatiles associated with malaria infection is exciting."
asymptomatic 【形】〔病気が〕身体に症状を現さない［引き起こさない］、無症状（性）の、無症候（性）の
He said more work was now needed to see if it could be made into a reliable test. 
The findings are being presented at this year's annual meeting of the American Society of Tropical Medicine and Hygiene.

20171106

'Big void' identified in Khufu's Great Pyramid at Giza

The mysteries of the pyramids have deepened with the discovery of what appears to be a giant void within the Khufu, or Cheops, monument in Egypt.It is not known why the cavity exists or indeed if it holds anything of value because it is not obviously accessible.

Japanese and French scientists made the announcement after two years of study at the famous pyramid complex.

They have been using a technique called muography, which can sense density changes inside large rock structures.
ミュオグラフィとはミュー粒子を使用するトモグラフィである
宇宙から降り注ぐ宇宙線の一種で透過力の強いミュー粒子の飛跡を元に透過した物体の密度分布を再構成する。これまで、火山のマグマ、溶鉱炉、ピラミッドの内部構造の調査や福島第一原子力発電所の炉心の現状を調査するためにも使用された。
The Great Pyramid, or Khufu's Pyramid, is thought to have been constructed during the reign of Pharaoh Khufu between 2509 and 2483 BC. At 140m (460 feet) in height, it is the largest of the Egyptian pyramids located at Giza on the outskirts of Cairo.
Khufu famously contains three large interior chambers and a series of passageways, the most striking of which is the 47m-long, 8m-high Grand Gallery.
The newly identified feature is said to sit directly above this and have similar dimensions.
"We don't know whether this big void is horizontal or inclined; we don't know if this void is made by one structure or several successive structures," explained Mehdi Tayoubi from the HIP Institute, Paris. 
"What we are sure about is that this big void is there; that it is impressive; and that it was not expected as far as I know by any sort of theory."
The ScanPyramids team is being very careful not to describe the cavity as a "chamber". 
Khufu contains compartments that experts believe may have been incorporated by the builders to avoid collapse by relieving some of the stress of the overlying weight of stone.
The higher King's Chamber, for example, has five such spaces above it.
The renowned American archaeologist Mark Lehner sits on a panel reviewing ScanPyramids' work.
He says the muon science is sound but he is not yet convinced the discovery has significance.
"It could be a kind of space that the builders left to protect the very narrow roof of the Grand Gallery from the weight of the pyramid," he told the BBC's Science In Action programme. 
"Right now it's just a big difference; it's an anomaly. But we need more of a focus on it especially in a day and age when we can no longer go blasting our way through the pyramid with gunpowder as [British] Egyptologist Howard Vyse did in the early 1800s."
in a day and age 今日では
One of the team leaders, Hany Helal from Cairo University, believes the void is too big to have a pressure-relieving purpose, but concedes the experts will debate this. 
"What we are doing is trying to understand the internal structure of the pyramids and how this pyramid has been built," he told reporters. 
"Famous Egyptologists, archaeologists and architects - they have some hypotheses. And what we are doing is giving them data. It is they who have to tell us whether this is expected or not."
Much of the uncertainty comes down to the rather imprecise data gained from muography.
This non-invasive technique has been developed over the past 50 years to probe the interiors of phenomena as diverse as volcanoes and glaciers. It has even been used to investigate the failed nuclear reactors at Fukushima.
Muography makes use of the shower of high-energy particles that rain down on the Earth's surface from space.
When super-fast cosmic rays collide with air molecules, they produce a range of "daughter" particles, including muons.These also move close to the speed of light and only weakly interact with matter. So when they reach the surface, they penetrate deeply into rock. 
But some of the particles will be absorbed and deflected by the atoms in the rock's minerals, and if the muon detectors are placed under a region of interest then a picture of density anomalies can be obtained.
 The ScanPyramids team used three different muography technologies and all three agreed on the position and scale of the void. 
Sebastien Procureur, from CEA-IRFU, University of Paris-Saclay, emphasised that muography only sees large features, and that the team's scans were not just picking up a general porosity inside the pyramid.
porosity 【名】穴がたくさんあること、多孔性、有孔性
"With muons you measure an integrated density," he explained. "So, if there are holes everywhere then the integrated density will be the same, more or less, in all directions, because everything will be averaged. But if you see some excess of muons, it means that you have a bigger void.  
"You don't get that in a Swiss cheese."   
The question now arises as to how the void should be investigated further.
Jean-Baptiste Mouret, from the French national institute for computer science and applied mathematics (Inria), said the team had an idea how to do it, but that the Egyptian authorities would first have to approve it.
"Our concept is to drill a very small hole to potentially explore monuments like this. We aim to have a robot that could fit in a 3cm hole. Basically, we're working on flying robots," he said.
The muography investigation at Khufu's Pyramid is reported in this week's edition of Nature magazine.

20171104

Beware potential signs of pancreatic cancer
One in three adults might ignore potential symptoms of pancreatic cancer, according to a charity.
Stomach ache, indigestion, unexplained weight loss and faeces that float rather than sink in the lavatory can be warning signs of the potentially deadly disease, says Pancreatic Cancer UK.
Early detection and treatment are vital to save lives.
Nikki Davies was diagnosed in March, aged 51. Her tumour was caught early, meaning a surgeon could remove it.
"I have been incredibly lucky that mine could be operated on and hadn't spread, as far as we can tell.
as far as we can tell分かる範囲では、恐らく
"My message to others would be that no-one knows your body like you do. 
"Know what the symptoms are and talk to your GP if you notice anything that's unusual for you.
"Deep down, I think you know something is wrong.
 deep down 心の底［中］では（本当は）、本心では、内心（で）は
"For me, it was the pain. It felt like an animal was eating me from the inside. It was in my back too, between my shoulder blades. And I'd lost a lot of weight very quickly.
shoulder blade《医》肩甲骨
"I didn't know anything about pancreatic cancer before my diagnosis, and I certainly wouldn't have known what the symptoms were." 
Know the signs
Currently, about one in 10 people diagnosed with the condition survives beyond five years. 
Hollywood actor Patrick Swayze died from advanced pancreatic cancer aged 57
This is in large part due to most patients being diagnosed at a late stage, when treatment options are very limited, says Pancreatic Cancer UK. 
Its survey of 4,000 UK adults suggests awareness of the symptoms is still too low.  
Alex Ford, chief executive at Pancreatic Cancer UK, said: "We do not want people to panic if they have some or all of these symptoms, because most people who have them will not have pancreatic cancer.
"But it is vital that people know more about this disease, and talk to their GP if they have any concerns.
"The earlier people are diagnosed, the more likely they are to be able to have surgery, which is the one treatment which can save lives."
Common symptoms of pancreatic cancer include:
stomach and back ache
unexplained weight loss
indigestion
changes to bowel habits, including floating faeces
bowel habit  排便習慣
Other symptoms include:
loss of appetite
jaundice (yellow skin or eyes or itchy skin)
feeling and being sick
difficulty swallowing
recently diagnosed diabetes

20171101

Record surge in atmospheric CO2 seen in 2016
Emissions from human activities have levelled off but concentrations in the atmosphere continue to grow
Concentrations of CO2 in the Earth's atmosphere surged to a record high in 2016, according to the World Meteorological Organization (WMO).
leveling-off【名】横ばい状態、安定状態
Last year's increase was 50% higher than the average of the past 10 years.
Researchers say a combination of human activities and the El Nino weather phenomenon drove CO2 to a level not seen in 800,000 years.
Scientists say this risks making global temperature targets largely unattainable.
unattainable 【形】〔目標などが〕達成不可能な
This year's greenhouse gas bulletin produced by the WMO is based on measurements taken in 51 countries. Research stations dotted around the globe measure concentrations of warming gases including carbon dioxide, methane and nitrous oxide.
bulletin【名】 〔官公庁からの〕公報、公示
The figures published by the WMO are what's left in the atmosphere after significant amounts are absorbed by the Earth's "sinks", which include the oceans and the biosphere.
2016 saw average concentrations of CO2 hit 403.3 parts per million, up from 400ppm in 2015.
"It is the largest increase we have ever seen in the 30 years we have had this network," Dr Oksana Tarasova, chief of WMO's global atmosphere watch programme, told BBC News.
"The largest increase was in the previous El Nino, in 1997-1998, and it was 2.7ppm; and now it is 3.3ppm. It is also 50% higher than the average of the last 10 years." 
El Nino impacts the amount of carbon in the atmosphere by causing droughts that limit the uptake of CO2 by plants and trees. 
Emissions from human sources have slowed down in the last couple of years according to research, but according to Dr Tarasova, it is the cumulative total in the atmosphere that really matters as CO2 stays aloft and active for centuries.
cumulative 【形】累積する
Over the past 70 years, says the report, the increase in CO2 in the atmosphere is nearly 100 times larger than it was at the end of the last ice age.
Rapidly increasing atmospheric levels of CO2 and other gases have the potential, according to the study, to "initiate unpredictable changes in the climate system... leading to severe ecological and economic disruptions".
The study notes that since 1990 there has been a 40% increase in total radiative forcing. That's the warming effect on our climate of all greenhouse gases.
radiative forcing  放射強制
"Geological-wise, it is like an injection of a huge amount of heat," said Dr Tarasova.
wise 【名】〔行動・判断などが〕分別［良識］ある、思慮深い
"The changes will not take 10,000 years, like they used to take before; they will happen fast. We don't have the knowledge of the system in this state; that is a bit worrisome!" 
According to experts, the last time the Earth experienced a comparable concentration of CO2 was three to five million years ago, in the mid-Pliocene Epoch. The climate then was 2-3C warmer, and sea levels were 10-20m higher due to the melting of Greenland and the West Antarctic ice sheets.
Pliocene epoch 鮮新世
Other experts in the field of atmospheric research agreed that the WMO findings were a cause for concern.
"The 3ppm CO2 growth rate in 2015 and 2016 is extreme - double the growth rate in the 1990-2000 decade," Prof Euan Nisbet from Royal Holloway University of London, UK, told BBC News. 
"It is urgent that we follow the Paris agreement and switch rapidly away from fossil fuels. There are signs this is beginning to happen, but so far the air is not yet recording the change." 
Another concern in the report is the continuing, mysterious rise of methane levels in the atmosphere, which were also larger than the average over the past 10 years. Prof Nisbet says there is a fear of a vicious cycle, where methane drives up temperatures which in turn releases more methane from natural sources.
"The rapid increase in methane since 2007, especially in 2014, 2015, and 2016, is different. This was not expected in the Paris agreement. Methane growth is strongest in the tropics and sub-tropics. The carbon isotopes in the methane show that growth is not being driven by fossil fuels. We do not understand why methane is rising. It may be a climate change feedback. It is very worrying." 
The implications of these new atmospheric measurements for the targets agreed under the Paris climate pact are quite negative, say observers.
"The numbers don't lie. We are still emitting far too much and this needs to be reversed," said Erik Solheim, head of UN Environment. 
"We have many of the solutions already to address this challenge. What we need now is global political will and a new sense of urgency."
The report has been issued just a week ahead of the next instalment of UN climate talks, in Bonn. Despite the declaration by President Trump that he intends to take the US out of the deal, negotiators meeting in Germany will be aiming to advance and clarify the rulebook of the Paris agreement.

20171029

Superbug 'sleuthing' finds secret outbreaks
A feat of "genomic sleuthing" has uncovered 173 secret outbreaks of the superbug MRSA, a study shows.
sleuth 【自動】捜索［探索］する
feat 【名】功績 妙技、業績
They were found in the east of England over the course of just one year, according to the details published in Science Translational Medicine.
over the course of ～のうちに、～の間に、～にわたって
The researchers say their approach could transform the way we tackle MRSA and other superbugs.
Detecting outbreaks that are happening under our noses should cut the number of people infected.
MRSA - or methicillin-resistant Staphylococcus aureus - is a bacterial infection that is resistant to a number of widely-used antibiotics
It can cause life-threatening infections if the bug breaches the skin, such as through a surgical wound
Detective work
Hospitals in the UK have become very good at catching outbreaks of MRSA, especially when they happen in the same place at the same time - such as in one hospital ward.
But MRSA also spreads outside of hospitals, in people's homes, in care homes; and patients and staff also move around from place to place.
Doctors will see the individual cases, but cannot always spot the bigger picture and catch the outbreak.
Prof Sharon Peacock, one of the researchers, told the BBC: "Patients move around wards very quickly and you don't always spot the links Sherlock Holmes might detect, but the genomics does it for you."
The team at the Wellcome Trust Sanger Institute sequenced the genetic code of every single MRSA sample that came through three hospitals and 75 GP surgeries.
They then pieced together the clues in a feat of genetic genealogy.
genealogy  【名】 （家）系図、系譜
piece together  【句他動】 〔情報などの断片をつないで〕全貌を知る
By looking at the genetic code, the researchers could work out which samples were closely related and therefore part of the same outbreak.
Surprise
They found 173, ranging from outbreaks affecting two patients up to 44.
"I was surprised by how many we detected," Prof Peacock said.
She added: "This could reverse the way we do infection control to be much more targeted, efficient and effective."
This strategy cannot prevent an outbreak from occurring, but it can nip it in the bud.
It is possible to get rid of MRSA, which mostly lives up the nose or on skin, using creams and antiseptic baths. 
A smaller scale version of this study managed to track down the carrier of MRSA and bring an outbreak in a baby unit to an end. 
Huge advances in DNA sequencing mean the whole genome of a bacterium can be worked out in a day for around ￡120.
 The researchers are about to start a trial investigating the cost-effectiveness of introducing genomic detective-work into the NHS.
Dr Jonathan Pearce, the head of infections and immunity at the UK's Medical Research Council, said: "This study sheds light on MRSA transmission within and between hospitals and the community, which could help strengthen infection prevention and control measures."

20171025

Patients need rest, not antibiotics, say health officials
More patients should be told to go home and rest rather than be given antibiotics, according to health officials.
Public Health England (PHE) says up to a fifth of antibiotic prescriptions are unnecessary as many illnesses get better on their own.
Overusing the drugs is making infections harder to treat by creating drug-resistant superbugs.
PHE says patients have "a part to play" in stopping the rise of infections.
It is estimated:
5,000 people die in England each year as a result of drug-resistant infections
Four in 10 cases of bloodstream E. coli infections now cannot be treated with first-choice antibiotics
By 2050, drug-resistant infections around the world are expected to kill more people than currently die from cancer
Antibiotics are vital in cases of sepsis, pneumonia, bacterial meningitis and other severe infections.
But PHE says antibiotics are not essential for every illness.
Coughs or bronchitis can take up to three weeks to clear on their own, but antibiotics reduce that by only one to two days, it says.
Prof Paul Cosford, medical director at PHE, told the BBC: "We don't often need antibiotics for common conditions.
"The majority of us will get infections from time to time and will recover because of our own immunity."
He said patients should not go to their doctor "expecting an antibiotic".
Instead, for infections that our body can handle, the advice is to:
have plenty of rest
use pain relief such as paracetamol
drink plenty of fluids
paracetamol【名】パラセタモール鎮痛剤として利用される医薬品
Prof Cosford said: "A doctor will be able to tell you when an antibiotic is really necessary.
"The fact is if you take an antibiotic when you don't need it then you're more likely to have an infection that the antibiotics don't work for over the coming months."
The Keep Antibiotics Working campaign will also see patients handed leaflets explaining how long it normally takes to recover and the warning signs of serious illness.
Analysis: Antibiotic apocalypse
apocalypse 【名】〔ユダヤ教およびキリスト教の〕啓示書   〔一般的な〕啓示  《the ～》世の終末、大災害
Apocalypse
Bacteria are incredibly cunning - once you start attacking them with antibiotics, they find ways of surviving. People have died from bugs resistant to all antibiotics.
England's chief medical officer, Prof Dame Sally Davies, has already warned of a "post-antibiotic apocalypse".
If the drugs fail, then not only do infections become harder to treat, but common medical procedures such as caesarean sections and cancer treatments could become too risky.
The most serious drug-resistant infections are sent to PHE's laboratories at Colindale, north London, for analysis.
Prof Neil Woodford, the site's head of antimicrobial resistance, said the most potent antibiotics, like carbapenems, were failing more often.
He told the BBC: "If we go back to 2005/07, we were seeing these bacteria in maybe two to four cases per year.
"Last year we confirmed these resistant bacteria in over 2,000 cases."

20171022

Penguins die in 'catastrophic' Antarctic breeding season
It is the second catastrophic season for the southern penguins in five years
All but two Adelie penguin chicks have starved to death in their east Antarctic colony, in a breeding season described as "catastrophic" by experts.
It was caused by unusually high amounts of ice late in the season, meaning adults had to travel further for food.
It is the second bad season in five years after no chicks survived in 2015.
Conservation groups are calling for urgent action on a new marine protection area in the east Antarctic to protect the colony of about 36,000.
WWF says a ban on krill fishing in the area would eliminate their competition and help to secure the survival of Antarctic species, including the Adelie penguins.
WWF have been supporting research with French scientists in the region monitoring penguin numbers since 2010.
The protection proposal will be discussed at a meeting on Monday of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR).
The Commission is made up of the 25 members and the European Union.
Adelie penguins are the most southerly breeding bird in the world.
They are found along the Antarctic coast, and breed from October to February
They typically lay two eggs in nests made of stones, and parents take turns to incubate the eggs
Breeding adults may have to travel up to 30-75 miles (50-120 km) to catch food to then regurgitate for their chicks
regurgitate【他動】〔食物を〕吐き戻す
"This devastating event contrasts with the image that many people might have of penguins," Rod Downie, Head of Polar Programmes at WWF, said.
"The risk of opening up this area to exploratory krill fisheries, which would compete with the Adelie penguins for food as they recover from two catastrophic breeding failures in four years, is unthinkable.
"So CCAMLR needs to act now by adopting a new Marine Protected Area for the waters off east Antarctica, to protect the home of the penguins."

​

20171012

Asteroid close approach to test warning systems
An asteroid the size of a house is set to pass close to the Earth on Thursday.
The space rock will hurtle past our planet at a distance of about 42,000km (26,000 miles), bringing it within the Moon's orbit and just above the altitude of communication satellites.
Nasa scientists say there is no risk of an impact, but the flyby does provide them with the opportunity to test their asteroid-warning systems.
A global network of telescopes will be closely monitoring the object.
Paul Chodas, manager of Nasa's Centre for Near Earth Object Studies (CNEOS) at the Jet Propulsion Laboratory in California, told BBC News: "We are going to use this asteroid to practise the system that would observe an asteroid, characterise it and compute how close it is going to come, in case some day we have one that is on the way inbound and might hit."
in case念のため、万が一（～する場合）の用心に、万が一［もしもの場合］に備えて、何かあるといけないので、～するといけないから、万一～の場合には
inbound 【形】 入ってくる、到着する
'No threat'
The asteroid, called 2012 TC4, was first spotted five years ago.
It is estimated to be between 15m and 30m (50-100ft) in size, which is relatively small.
However, even space rocks on this scale are dangerous if they strike.
Nasa search programmes are getting better and better at finding asteroids
Paul Chodas, Centre for Near Earth Object Studies
When a 20m-wide asteroid exploded over Chelyabinsk in central Russia in 2013, it hit the atmosphere with energy estimated to be equivalent to 500,000 tonnes of TNT, causing a shockwave that damaged buildings and injured more than a thousand people.
Nasa scientists who have spent the last two months tracking this new rocky visitor say their calculations show that it will safely clear the Earth and poses no threat.
Instead, they will use this close approach to rehearse for future potential strikes.
More than a dozen observatories, universities and labs around the world will be watching 2012 TC4 as it flies past.
This will help them to refine how asteroids are tracked and provide a chance to test international communication systems.
Dr Chodas said that while the risk of an asteroid hit was small, it was prudent to plan ahead.
prudent 【形】 〔実務に関して〕分別のある、良識的な、堅実な 将来に備えた、倹約する
"Nasa search programmes are getting better and better at finding asteroids," he explained.
"It's been a priority to find the large asteroids first. So far the Nasa surveys have found 95% of the asteroids that are one kilometre and larger - these are the ones that could cause a global catastrophe.
"Now we are working our way down to the smaller ones - 130m in size and larger - and we are around 30% on that.
"This little one - we are not trying to find all of the ones of this size. It is just a convenient asteroid coming by that we can practise our tracking techniques on."
work one's way down a list リストを念入りに探す、上から順番にリストに当たる
work one's way down to   ～に入って行く
He added that if an asteroid was discovered to be heading for the Earth, scientists were looking at different techniques to avert a disaster.
"If we had enough warning time - five or 10 years - then we could do something about it, especially if it's on the small side.
"We could go up and move it, change its velocity years ahead, and that would be enough to move it away from a collision course."
Asteroid TC4's closest approach to Earth on Thursday will be over Antarctica at 05:42 GMT (06:42 BST; 01:42 EDT).