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David Freeman
David Freeman is the senior science editor of The Huffington Post in New York City and the host of Science Insider, a weekly radio program on an NPR station in Sharon, CT.

Entries by David Freeman

10 Mind-Boggling Science Facts That Will Make You Feel Grateful

(0) Comments | Posted November 25, 2015 | 12:44 PM

From the farthest reaches of the cosmos to the curious behavior of subatomic particles, science helps us understand our universe. But science can console as well as explain.

How does it do that? By helping us realize that some of our everyday problems are actually pretty puny.

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Novas descobertas sobre a estrutura do DNA podem levar a remédios mais eficazes

(1) Comments | Posted October 28, 2015 | 4:20 PM

Esqueça aquela escadinha estática que você aprendeu na aula de biologia. O DNA está em movimento o tempo todo e fica mudando de forma.

Você não precisa ser biólogo molecular para saber que o ácido desoxirribonucleico (DNA) tem uma estrutura de “dupla hélice”. Mas, se você acha que a molécula da vida não é nada além de “duas cadeias helicoidais enroladas em um mesmo eixo”, como descreveram Watson e Crick em 1953, pense de novo.

Os cientistas sabem agora que as moléculas de DNA se enrolam em si mesmas, formando superespirais bem apertadas, e novas pesquisas sobre os “minicírculos” do DNA realizadas por pesquisadores americanos e europeus mostram que o DNA está em movimento constante, tomando várias formas diferentes.

“Alguns dos círculos tinham cantos agudos, outros formavam um oito, outros pareciam algemas, raquetes ou até mesmo agulhas”, disse em comunicado Rossitza N. Irobalieva, ex-pesquisadora do Baylor College of Medicine e coautora do novo estudo.

“Alguns pareciam varetas, de tão enrolados.”

A descoberta é mais que simplesmente uma curiosidade científica. Os pesquisadores afirmam que ela pode levar a remédios melhores, incluindo drogas para tratar câncer e infecções bacterianas.

“Como algumas terapias anticâncer se conectam com o próprio DNA, e alguns antibióticos alvejam enzimas que reconhecem especificamente os DNA superenrolados das bactérias, esperamos que a pesquisa ajude a melhorar o design dos remédios desde o início do processo”, disse Sarah A. Harris, física teórica da Universidade de Leeds, Inglaterra, e co-autora do estudo.

Como os pesquisadores chegaram a essa nova imagem do DNA? Primeiro, os cientistas do Baylor College of Medicine fizeram pequenos círculos de DNA e usaram uma técnica de microscópio conhecida como tomografia de crioeletrônica para criar imagens detalhadas desses círculos.

Então, os cientistas da Universidade de Leeds usaram um supercomputador para simular como as moléculas se moviam e que forma tomavam.

O estudo, intitulado The Structural Diversity of Supercoiled DNA (a diversidade estrutural das super espirais de DNA, em tradução livre), foi publicado na revista Nature, em 12 de outubro de 2015.


Este artigo foi originalmente publicado pelo HuffPost US e traduzido do inglês.


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Neil deGrasse Tyson, de 'Cosmos', fala sobre ateísmo, alienígenas e como aprendeu a 'admirar o universo'

(1) Comments | Posted October 27, 2015 | 5:39 PM

"Tudo que sabemos e amamos sobre o universo e todas as leis da física se aplicam a 4% do universo. Isso é impressionante."

As coisas estão indo bem para Neil deGrasse Tyson. Bem mesmo. Como diretor do Hayden Planetarium e autor de vários livros conhecidos sobre...

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A Baldness Cure Isn't Here Yet, But New Research Is Promising

(0) Comments | Posted October 26, 2015 | 2:22 PM

No one is claiming a cure for baldness just yet, but researchers at Columbia University Medical Center may have taken an important step in that direction.

In a series of experiments involving mice and human tissue, the scientists showed that enzyme-blocking drugs known as JAK inhibitors can cause significant regrowth of hair when applied to the skin.

The unexpected finding raises the possibility that these medications might be used to restore hair growth in men and women experiencing pattern baldness, as well as in cancer patients who have lost hair as a result of chemotherapy treatments. Oral versions of the medicines have already been approved by the FDA to treat other medical conditions.

"What we've found is promising, though we haven't yet shown it's a cure for pattern baldness," Dr. Angela M. Christiano, associate professor of molecular dermatology at the center and the leader of the new research, said in a written statement. "More work needs to be done to test if JAK inhibitors can induce hair growth in humans using formulations specially made for the scalp."

More work, certainly. But that didn't stop hair loss experts from hailing the new research.

"This is a very exciting discovery," Dr. Nicole Rogers, a dermatologist and hair transplant surgeon in New Orleans, told The Huffington Post in an email. "It would be very exciting if this class of medicines could indeed solve the problem of male and female pattern hair loss. These conditions are the most common causes of hair loss and can be devastating when they occur in very young people."

The discovery grew out of research conducted by Christiano on alopecia areata, a form of hair loss that arises when the body's immune system attacks hair follicles. 

When JAK inhibitors were applied to the skin of normal mice whose bodies had been shaved, the mice grew more hair than mice that were given an oral preparation of the drugs. That suggested that the drugs were affecting hair follicles directly rather than simply blocking an errant immune response.

(Story continues below photos.)

Mice treated for five days with the JAK inhibitors ruxolitinib and tofacitinib grew new hair within 10 days (see photos above). No hair grew on untreated control mice during that timespan.

What explains the finding? JAK inhibitors apparently coax normal hairs out of their resting (telogen) phase and cause them to rapidly enter the growing (anagen) phase of the hair cycle, Christiano told The Huffington Post in an email.

The next step would be to conduct clinical trials, according to Christiano. Because the JAK inhibitors that the Columbia researchers tested are already FDA-approved, they could take less time to reach those in need, she said. However, it could still be four or five years before the drugs are commercially available for treating hair loss.

That's if they pan out at all.

Of course, a potent hair-regrowth drug can't come soon enough for many of the 35 million men and 21 million women affected by hair loss in the U.S. While two drugs have FDA approval for the treatment of hair loss, neither is considered a wholly reliable way to grow significant quantities of hair. 

A paper describing the research was published in the online edition of the journal Science Advances on Oct. 23,...

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스톤헨지는 고기 굽기를 좋아하는 사람들이 만든 것 같다

(0) Comments | Posted October 24, 2015 | 6:01 PM

우리는 스톤헨지를 어떻게, 왜 만들었는지 정확히 모른다. 그러나 약 4,500년 전 이 신비로운 기념비를 만든 사람들의 식습관에 대해서는 이제 알게 되었다.

그들은 무엇을 먹었는가? 바비큐다.

스톤헨지에서 몇 킬로미터 떨어진 신석기 시대의 주거지 더링턴 월에서 발굴된 동물 뼈와 수백 개의 도기 조각들을 체계적으로...

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This Physicist Says Dark Matter May Have Killed Off The Dinosaurs

(1) Comments | Posted October 21, 2015 | 12:24 PM

As every astronomy buff knows, dark matter is pretty elusive stuff.

We can't see it. We can't hear it or feel it, and we certainly can't smell or taste it. Even with the world's most sophisticated scientific gear, there's no direct proof that the long-hypothesized form...

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Are You Science-Literate? Take Our Quiz And Find Out

(0) Comments | Posted October 15, 2015 | 5:50 PM

How much do you know about science? You're about to find out.

From astronomy to physics, our fun but challenging science literacy quiz covers just about every discipline there is.

There are 44 questions. Each has only one correct answer. We've also included full explanations... 

Take as long as you...

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It Seems Stonehenge Was Built By Folks With A Thing For Barbecue

(1) Comments | Posted October 15, 2015 | 12:28 PM

We might not know precisely how Stonehenge was built--or why it was built. But now we know the eating habits of the people who are believed to have completed the mysterious monument more than 4,500 years ago.

And what was it...

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DNA Study Yields Big Surprise About The Tiny 'Molecule Of Life'

(0) Comments | Posted October 12, 2015 | 1:58 PM

You don't have to be a molecular biologist to know that deoxyribonucleic acid (DNA) has a "double helix" structure. But if you think the molecule of life is nothing more than the "two helical chains each coiled round the same axis" outlined by Watson and Crick in their classic 1953 paper, think again.

Scientists now know that DNA molecules twist repeatedly upon themselves to form tightly wound supercoils, and new research on DNA "minicircles" by scientists in the U.S. and Europe shows that DNA is constantly wiggling and morphing into a menagerie of different shapes.

"Some of the circles had sharp bends, some were figure-8s, and others looked like handcuffs or racquets or even sewing needles," Dr. Rossitza N. Irobalieva, formerly of Baylor College of Medicine in Houston and a co-author of a paper describing the research, said in a written statement. "Some looked like rods because they were so coiled."

(Story continues below gif.)

The finding represents more than a scientific curiosity. Scientists say it could pave the way to better medicines, including ones for treating cancer and bacterial infections.

"Since some anti-cancer therapies bind to the DNA itself, and some antibiotics target the enzymes that specifically recognize supercoiled DNA in bacteria, we hope that our research will improve the molecular design of drugs right from the very beginning of the process," Dr. Sarah A. Harris, a theoretical physicist at the University of Leeds in England and a co-author of the paper, told The Huffington Post in an email

How were the researchers able to arrive at this incredible new picture of DNA? First, scientists at Baylor made little circles of DNA and then used a microscopy technique known as cryo-electron tomography to create detailed images of them. Then scientists at Leeds University used a supercomputer to simulate how the molecules moved and what shapes they assumed.

The paper, entitled The Structural Diversity of Supercoiled DNA, was published online in the journal Nature Communications on Oct. 12,...

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Pluto Has Blue Skies And Red Ice, NASA Says

(0) Comments | Posted October 8, 2015 | 3:10 PM

NASA's New Horizons mission keeps revealing new surprises about Pluto.

The latest: The far-flung dwarf planet has blue skies and small patches of water ice on its surface.

"Who would have expected a blue sky in the Kuiper Belt?" Alan Stern, the mission's principal investigator, said...

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Neil deGrasse Tyson Talks God, Aliens, And Multiverses

(0) Comments | Posted October 5, 2015 | 12:30 PM

EDITOR'S NOTE: An earlier version of this story was published here.  

Things are looking up for Neil deGrasse Tyson--way up. As the director of the Hayden Planetarium and the author of several popular books on space, Tyson is already one of the nation's best-known scientists. And...

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Stunning New Charon Photos Reveal Pluto Moon's Violent Past

(0) Comments | Posted October 2, 2015 | 12:05 AM

NASA has released striking new images of Pluto's largest moon, Charon, and the world they show is very different from what the space agency's scientists had expected.

Many of the scientists had expected Charon to have a monotonous surface covered with craters, the agency said. Instead, the photos--taken by NASA's New Horizons spacecraft on July 14--reveal a landscape dotted with mountains, canyons, and landslides.

The high-resolution photos also show stark variations in Charon's surface color.

“We thought the probability of seeing such interesting features on this satellite of a world at the far edge of our solar system was low, but I couldn't be more delighted with what we see,” Dr. Ross Beyer, an affiliate of the New Horizons team from the SETI Institute and NASA Ames Research Center in Mountain View, California, said in a written statement.

(Story continues below images.)

Perhaps the most dramatic feature is a vast system of canyons that stretches more than 1,000 miles across Charon's face and likely onto the moon's far side. (The video above lets you fly through it.)

In case you're wondering, NASA says that's four times longer than the Grand Canyon and in some places twice as deep. As Dr. John Spencer, a New Horizons scientist affiliated with the Southwest Research Institute in Boulder, Colorado, said in the statement, "It looks like the entire crust of Charon has been split open.”   

The New Horizons spacecraft, now 3.1 billion miles from Earth, is still sending data about Pluto and its moons back to Earth. So, impressive as the new photos are, NASA says even better images are yet to...
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Why Bill Nye Is So Pumped About The Mars Water Discovery

(1) Comments | Posted September 29, 2015 | 5:26 PM

Bill Nye is positively gushing about the recent discovery of liquid water on Mars--not so much about the water itself but about what its presence means for the chances that the red planet harbors life.

"With salty water flowing every Martian year, it is very reasonable that there...

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Watch NASA's 'Mars Mystery Solved' Press Briefing Right Here

(3) Comments | Posted September 26, 2015 | 9:42 PM

NASA will hold a press briefing at 11:30 a.m. EDT on Monday, Sept. 28 to detail what the space agency calls a "major science finding" from its ongoing exploration of Mars. You can watch it here.

What will NASA be reporting? Some have speculated that the space agency might report the discovery of life on Mars. Others think it might report the discovery of liquid water, which is considered a key ingredient for a planet's suitability for life

Whatever it is, we'll just have to wait and see what NASA has up its sleeve.

NASA says members of the public are welcome to pose questions to the participants of the briefing using the hashtag #AskNASA.

The participants include:

  • Jim Green, director of planetary science at NASA headquarters in Washington, D.C.
  • Michael Meyer, lead scientist for the agency's Mars Exploration Program, also at NASA headquarters.
  • Lujendra Ojha, a Ph.D. candidate in planetary science at Georgia Institute of Technology in Atlanta.
  • Mary Beth Wilheim, of NASA's Ames Research Center in Moffett Field, California and Georgia Institute of Technology
  • Alfred McEwen, principal investigator for the High Resolution Imaging Science Experiment (HiRISE) at the University of Arizona in Tucson.


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RECAP: Dramatic Eclipse Photos

(0) Comments | Posted September 25, 2015 | 3:39 PM

After weeks of anticipation, the supermoon lunar eclipse finally arrived.

The long-awaited “blood moon” stunned stargazers on Sunday night. It was visible across the U.S. starting at 9:07 p.m. EDT.  In case you missed it, check out some spectacular new photos of the eclipse, below, taken by skywatchers and professional astronomers.

A photo posted by Todd Carr (@photofox5000) on

A photo posted by Valentine (@valissa7) on

A photo posted by dgold911 (@dgold911) on

A photo posted by Craig (@craigmo71) on

More specific times, courtesy of EarthSky. 

Eastern Daylight Time (Sept. 27, 2015)
Partial umbral eclipse begins: 9:07 p.m. EDT on Sept. 27
Total eclipse begins: 10:11 p.m. EDT
Greatest eclipse: 10:47 p.m. EDT
Total eclipse ends: 11:23 p.m. EDT
Partial eclipse ends: 12:27 a.m. EDT on Sept. 28

Central Daylight Time (Sept. 27, 2015)
Partial umbral eclipse begins: 8:07 p.m. CDT on Sept. 27
Total eclipse begins: 9:11 p.m. CDT
Greatest eclipse: 9:47 p.m. CDT
Total eclipse ends: 10:23 p.m. CDT
Partial eclipse ends: 11:27 p.m. CDT

Mountain Daylight Time (Sept. 27, 2015)
Partial umbral eclipse begins: 7:07 p.m. MDT on Sept. 27
Total eclipse begins: 8:11 p.m. MDT
Greatest eclipse: 8:47 p.m. MDT
Total eclipse ends: 9:23 p.m. MDT
Partial eclipse ends: 10:27 p.m. MDT

Pacific Daylight Time (Sept. 27, 2015)
Partial umbral eclipse begins: 6:07 p.m. PDT on Sept. 27
Total eclipse begins: 7:11 p.m. PDT
Greatest eclipse: 7:47 p.m. PDT
Total eclipse ends: 8:23 p.m. PDT
Partial eclipse ends: 9:27 p.m....

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America Is Throwing Out Way More Garbage Than We Thought

(2) Comments | Posted September 24, 2015 | 3:00 PM

If you worry that Americans produce too much garbage, you won’t get much reassurance from a new study published in the journal Nature Climate Change.

The study shows that landfills across the country are taking in more than twice as much solid waste as the government thought: a whopping 262 million tons of food scraps, paper products, and the like in 2012 rather than the 122 million tons that the EPA had estimated for that year.

In more personal terms, the new estimate suggests that our landfills are taking in roughly five pounds of solid waste per person per day, according to the Associated Press.

(Story continues below map.)

What explains the jarring discrepancy between the new estimate and EPA’s? It’s all about methodology.

The EPA traditionally has based its estimate on reports from businesses, industry associations, the U.S. Census, and other sources, according to a written statement released by Yale University.

Instead, the researchers behind the new study went directly to the operators of more than 1,200 municipal solid waste landfills across the nation, using four years of data through 2013. That makes the new estimate a “superior number,” Jon Powell, a Ph.D. student in Yale’s department of chemical and environmental engineering and the lead author of a paper describing the research, said in the statement.

“I am excited about the possibilities that the quality-assured, measured data we were able to leverage in this study holds in terms of informing our path forward to manage wastes more sustainably,” Powell told The Huffington Post in an email.

The nation isn’t about to run out of landfill space anytime soon. In fact, the new research suggests that the average landfill has enough capacity for another 30 to 40 years of use.

But the landfills that have more space can be far away from the cities that need their services, Dr. Morton Barlaz, head of the department of civil, construction and environmental engineering at North Carolina State University, told LiveScience. Barlaz was not involved in the new study.

And then there’s the fact that landfills give off lots of gas—including methane, which contributes to global warming. In fact, the decomposition of municipal waste in landfills is considered one of the world’s largest sources of human-produced methane emissions, according to the statement.

(Story continues below map.) 

The new study may encourage researchers to develop better ways to curb the release of methane from landfills, according to Science magazine.  

What else can be done to mitigate our garbage problem? According to Powell, "There are many interconnected factors that impact the production of waste--mass of raw materials used, durability of goods, individual behavior, to name a few."

Time to reconsider how much you throw away every...

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12 Fascinating Facts About Your Lips

(0) Comments | Posted September 24, 2015 | 2:34 PM

Lips are, of course, essential for eating and speaking. And whistling. And kissing. And we'd look pretty silly without them. 

But if you think that's all there is to say--and know--about human lips, you're in for a big surprise. Just take a look at our list of 12 fascinating facts...

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No, The 'Blood Moon' Doesn't Mean Doomsday Is Here

(0) Comments | Posted September 23, 2015 | 1:55 PM

Here's some welcome news for anyone who is worried--as some fundamentalists might be--that the upcoming "blood moon" means the world is coming to an end:

It isn't.

Astronomically speaking, "there is no such thing as a 'blood moon,'" Dr. Jay Pasachoff, an astronomer at Williams College in Williamstown, Mass., told The Huffington Post in an email. People who use that term are either "misguided or malicious," he added.

The moon will look reddish for a brief time on the night of Sept. 27-28. But that's only because the moon will be cast into shadow as the Earth passes between it and the sun--in other words, we're set to see a lunar eclipse.

In the U.S., the eclipse will begin at 9:07 p.m. E.T. and will last for more than three hours. What astronomers call "totality"--when the moon is fully enveloped within the Earth's shadow--will begin at 10:11 p.m. and last for 72 minutes.

Fair enough. But why exactly will the moon take on that crimson cast?

In a new video (above) posted on its website, NASA suggests a simple thought experiment can make it all clear:

Using your imagination, fly to the Moon and stand inside a dusty lunar crater. Look up. Overhead hangs Earth, nightside facing you, completely hiding the sun behind it. The eclipse is underway. You might suppose that the Earth overhead would be completely dark. After all, you're looking at the nightside of our planet. Instead, something amazing happens. When the sun is located directly behind Earth, the rim of the planet seems to catch fire! The darkened terrestrial disk is ringed by every sunrise and every sunset in the world, all at once. This light filters into the heart of Earth's shadow, suffusing it with a coppery glow. Back on Earth, the shadowed Moon becomes a great red orb.

In more scientific terms, the moon looks red during a lunar eclipse because of Rayleigh scattering. That's a phenomenon in which sunlight--essentially a mash-up of all the different colors of light--is scattered by Earth's atmosphere. Since blue light is scattered more than red light, it's essentially "filtered out" as it passes through the atmosphere--leaving red light to reach the moon.

You don't need any special equipment to see a lunar eclipse. But watching the action unfold with a telescope or binoculars will add to the fun. As astronomer Phil Plait wrote recently on  Slate, "The moon can take on an odd three-dimensional appearance when you use binoculars during an eclipse, and it's pretty cool to see."

This is the last total lunar eclipse until 2018, according to Sky & Telescope. So enjoy the show!

Correction: A previous version of this story misstated the relative positions of the Earth, moon, and sun that occur during a lunar eclipse.

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15 Of Richard Dawkins' Most Controversial Tweets

(1) Comments | Posted September 21, 2015 | 2:50 PM

For better or worse, Richard Dawkins simply isn't one to bite his tongue.

On Sunday, the outspoken evolutionary biologist and best-selling author took to Twitter to suggest that Ahmed Mohamed, the Texas teen who was arrested last week after showing up at school with a clock...

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If You Like To Blow S*** Up, Check Out These Chemistry GIFs

(0) Comments | Posted September 17, 2015 | 5:24 PM

Chemistry can be a blast--literally.
Just consider what happens when you seal dry ice (solid carbon dioxide) in a bottle and submerge it in hot water. Via a process known as sublimation, the dry ice turns into gaseous carbon dioxide,...
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