Archive for 2 de February de 2017

By Karl Tate, Infographics Artist

On Feb. 1, 2003, the shuttle Columbia was returning to Earth after a successful 16-day trip to orbit, where the crew conducted more than 80 science experiments ranging from biology to fluid physics. However, the seemingly healthy orbiter had suffered critical damage during its launch, when foam from the fuel tank’s insulation fell off and hit Columbia’s left wing, tearing a hole in it that later analysis suggested might have been as large as a dinner plate.

The damage occurred just after Columbia’s liftoff on Jan. 16, but went undetected. During re-entry, the hole in a heat-resistant reinforced carbon carbon panel on Columbia’s left wing leading edge allowed super-hot atmospheric gases into the orbiter’s wing, leading to its destruction.

Killed in the Columbia shuttle disaster were STS-107 mission commander Rick Husband and included pilot Willie McCool, mission specialists Kalpana Chawla, Laurel Clark and David Brown, payload commander Michael Anderson and payload specialist Ilan Ramon, Israel’s first astronaut. [Share Your Thoughts on Columbia]

Poll: Is Human Spaceflight Worth the Risk?

A subsequent inquiry by the Columbia Accident Investigation Board (CAIB) faulted NASA’s internal culture as much as the foam strike as causes of the shuttle disaster. The Columbia accident ultimately led then-President George W. Bush to announce plans to retire NASA’s space shuttle fleet (which was more than 20 years old at the time) once construction of the International Space Station was complete. A capsule-based spacecraft was planned to replace the shuttles. [Photos: The Columbia Space Shuttle Tragedy]

NASA’s space shuttle fleet resumed launches in July 2005, after spending more than two years developing safety improvements and repair tools and techniques to avoid a repeat of the Columbia disaster. In 2011, NASA launched the final space shuttle mission, STS-135, to complete the shuttle fleet’s role in space station construction.

Video: Remembering Columbia’s Crew – ‘In Their Own Words’

In 2012, NASA’s three remaining shuttles – Discovery, Atlantis and Endeavour – were delivered to museums in Washington, D.C., Florida and California, while the test shuttle Enterprise was delivered to New York City. Under President Barack Obama, NASA was directed to rely on private spacecraft to launch Americans to the International Space Station and return them to Earth. NASA, meanwhile, is developing a new giant rocket – the Space Launch System – and the Orion space capsule for future deep-space missions to an asteroid, the moon and Mars.





How to control the subjective experience of time.



Imagem relacionada

image edited by Web Investigator 

And so is the past. Migration and mingling are essential to human success in the past, the present and into the future

Scott Solomon is a biologist and science writer. He teaches biosciences at Rice University, and his writing and photography have appeared in Slate, Nautilus and, among others. His latest book is Future Humans: Inside the Science of Our Continuing Evolution (2016). He lives in Houston, Texas.

In the future, a lot of people might look like Danielle Shewmake, a 21-year-old college student from Fort Worth, Texas. Shewmake has dark, curly hair, brown eyes, and an olive skin tone that causes many to mistake her heritage as Mediterranean. Her actual pedigree is more complex. Her father is half-Cherokee and half-Caucasian, and her mother, who was born in Jamaica, is the child of an Indian mother and an African and Scottish father.

‘My sister and I are just a combination of all that,’ she says, adding that she dislikes having to pick a particular racial identity. She prefers the term ‘mixed’.

Differences in physical traits between human populations accumulated slowly over tens of thousands of years. As people spread across the globe and adapted to local conditions, a combination of natural selection and cultural innovation led to physical distinctions. But these groups did not remain apart. Contact between groups, whether through trade or conflict, led to the exchange of both genes and ideas. Recent insights from the sequencing of hundreds of thousands of human genomes in the past decade have revealed that our species’ history has been punctuated by many episodes of migration and genetic exchange. The mixing of human groups is nothing new.

What is new is the rate of mixing currently underway. Globalisation means that our species is more mobile than ever before. International migration has reached record highs, as has the number of interracial marriages, leading to a surge of multiracial people such as Shewmake. While genetic differences between human populations do not fall neatly along racial lines, race nevertheless provides insight into the extent of population hybridisation currently underway. This reshuffling of human populations is affecting the very structure of the human gene pool.

Archaeological evidence suggests that Homo sapiens came into existence roughly 200,000 years ago in east Africa. By 50,000 years ago (but possibly earlier) people had begun to spread out of Africa, across the Arabian Peninsula and into Eurasia, perhaps driven by a changing climate that necessitated a search for new food sources. They made their way across now flooded land bridges to reach Australia and the Americas, and eventually came to inhabit even the most remote Pacific islands.

Evidence of these ancient migrations can be found by examining the DNA of living people as well as DNA recovered from ancient skeletons. In some cases, the genome studies corroborate archaeological and historical records of human movements. The Mongol Empire, the Arab slave trade, the spread of Bantu-speaking peoples across much of Africa and the effects of European colonialism have all left a predictable record within our genomes. In other cases, the genetic data provide surprises and can help archaeologists and historians settle controversies. For example, until recently, it was thought that the Americas were settled by a single wave of nomads who travelled across a land bridge spanning the Bering Strait. But recent genome analyses, which include samples from a wide range of indigenous groups, suggest that the Americas might have been colonised by at least four independent waves of settlers.

We are a restless species, and our genomes reveal that even the most intimidating geographical barriers have managed only to somewhat restrict human movements. Today, international migration is increasing at 1 to 2 per cent per year, with 244 million people in 2015 living in a country other than the one in which they were born. The biological implications of this massive experiment in interbreeding we are now witnessing will not be known for generations. But applying what we know about genetics and evolution can help us predict our future, including whether humans will be able to continue adapting to the constantly changing conditions on Earth.

Biological adaptation is a result of natural selection, and natural selection requires diversity. Think of natural selection like a sieve separating one generation from the next. Only the genes from those individuals that are well suited to their environment at that time will reproduce, passing their genes through the sieve to the next generation. Changing conditions alter the shape of the sieve’s holes and thereby which genes can pass through. The more variation there is in the population, the better the chances that some genes present in a generation will be able to pass through the sieve and be inherited by future generations. Unfortunately for us, humans are not very diverse…





by Tracy Moore

Well, shit

When it comes to sex, one adage holds true: Doing it is a lot different than talking about it, and people have wildly different ideas about how to discuss sex, particularly when it comes to sexual history. Should you tell someone how many people you’ve slept with? What does your number mean, anyway? It’s different if you’re a man! One survey found that 22 percent of people never reveal how many people they’ve slept with, with another 30 percent waiting until a relationship was exclusive to dish.

All this anxiety about when or if to reveal the number hinges on the fact that, high or low, we don’t know how a new partner will react. Though common sense tells us somewhere between virgin and gigolo is probably fine, once you put it out there, there’s no taking it back. That said, a new study suggests there’s a just-right number of previous partners — and claims that, at least in the case of a potential long-term relationship, the ideal number is three. That’s right. Three. But before you feel too embarrassed about your number, the average age in the study was 21.

In the paper, published this month in the Journal of Sex Research, researchers Steve Stewart-Williams, Caroline Butler and Andrew G. Thomas looked at how sexual history affects attractiveness. The study was based on survey results from 188 adults; its findings contradict the results of a survey published last year that showed the ideal number as a little over seven.

But contrary to the previously reported study that the ideal average number of sex partners is around seven, they found that men and women both preferred their partners have less than half that number. What gives? We spoke to Stewart-Williams by email and asked him to parse the results for us.

In research like this, I always first wonder how reliable any self-reported performance like sex can be. Won’t men overstate past partners and women will understate? Are you able to account for such things?
There’s a fair amount of research looking at how accurate self-report methods really are. The short answer is that they’re not completely reliable — no method is. But as a general rule, people’s responses on anonymous surveys tend to be quite accurate and tend to correlate quite well with more objective measures.

What does this study tell us about young men’s attitude toward sex today? Women’s?
Our main finding was that most people — men and women — are reluctant to get involved with someone with a very high number of past sexual partners. They’re much more willing to get involved with someone with a more modest number: between zero and 10. Within the zero-to-10 range, we found that people generally preferred someone with a handful of past partners to someone who had no partners at all. In other words, they prefer someone with a bit of a past but not too much (which is the title of our paper).

The pattern was surprisingly similar for both sexes. When we asked about long-term relationships, there were basically no sex differences in how willing people were to get involved with a person with a given number of past sexual partners. For flings and casual relationships, on the other hand, there was a small sex difference: Men were more willing than women to get involved, regardless of how many past partners the person had had. But even for casual relationships, both sexes tended to prefer someone with a handful of partners, rather than a lot of handfuls. The study was done in the U.K., by the way, and it’s very likely we’d get different results in other cultures…




by Jesse Jarnow, The InfluenceWaking Times

Editor’s Note: This article was originally published by The Influence, and is reprinted here with permission.

Known in drug lore as “the businessman’s trip” for its lunch-break-sized 15-minute duration, DMT (N,N-dimethyltryptamine) is infamous for blasting its users into vivid alien worlds. It’s among the most literally hallucinogenic of all the psychedelics. Now, a pair of veteran researchers have proposed a method to safely extend the experience beyond its short length.

Dr. Rick Strassman and Dr. Andrew Gallimore published their paper in Frontiers in Psychology last month, under the name “A Model for the Application of Target-Controlled Intravenous Infusion for a Prolonged Immersive DMT Psychedelic Experience.” Its implications could turn DMT research on its head, allowing for new scientific (and potentially, medical) insights into the principle ingredient in ayahuasca.

Using techniques borrowed from anesthesiology, the method will regulate the amount of DMT in the body and, more importantly, the brain. Though still untested on no-doubt-willing psychonauts, Strassman and Gallimore’s technology is all but ready for assembly.

Strassman, author of DMT: The Spirit Molecule (2001) and DMT and the Soul of Prophecy (2014) and the world’s foremost clinical DMT researcher, argues that the substance provides access to what users experience as mystical states, comparable to those described in the Hebrew Bible.

Dr. Rick Strassman

Gallimore, a computational neurobiologist, is also a historical scholar of DMT. His overview “DMT Research from 1956 to the Edge of Time” recounts a wide range of possibilities that researchers have offered over the years (including the notion that DMT is a doorway into an alternate universe). Other theories involve its role in human brain at the time of death, as well as countless South American beliefs inseparable from ayahuasca and DMT snuff traditions. Perhaps the only universal experience of smoked DMT is its brevity.

“DMT has a number of pharmacological peculiarities,” says British-born Gallimore, who is also a chemist and pharmacologist, and currently works at the Okinawa Institute of Science and Technology in Japan.

Dr. Andrew Gallimore

Besides being nontoxic, he says, “it’s very short acting, and it doesn’t exhibit subjective tolerance with repeated use. This is quite remarkable, because all other psychedelics exhibit very rapid tolerance, so you have to wait for days before you can get the same effect. This lack of subjective tolerance suggested to me that you could use a continuous drip-feed of DMT rather than a bullous injection, which is what Rick used [in his ‘90s studies]. It gets a very rapid peak effect. And that’s fine for the work he wanted to do. But if you want to study the DMT state more thoroughly…”

Both Gallimore and Strassman had come across a 2005 German study that attempted to extend the DMT state, but neither was satisfied with the methodology, the data, nor the results, which seemed to indicate a number of freaked-out volunteers.

“My idea was to think about what anesthesiologists do,” says Gallimore. “It’s a really interesting area of medicine. A lot of modern anesthesiology is based on the pharmacokinetic models of these drugs that allow you to simulate the level of drug in the brain. Using this model, you can actually program an infusion machine, to control the infusion rate of the drug such that the level of the drug remains a constant level within some particular window with some degree of accuracy.”

Recalling that Strassman had collected “pharmacokinetic curves… of DMT in the blood over time,” he contacted Strassman, who is based in New Mexico, and asked if he could use his blood sample data to create the new model. And so their collaboration was born.

“The psychotherapeutic applications of a continuous infusion are appealing,” says Strassman. “This would be an extension of the repeated dose study [detailed in DMT: The Spirit Molecule] where we found that it was extremely useful for volunteers to be able to process what they had just undergone—now in a relatively sober state for the 5-10 minutes of clarity between doses—in preparation for the upcoming session. There seemed to be a progression of themes and content throughout the morning, and working with trained psychotherapists optimized whatever psychological work they were accomplishing during those sessions.”

It’s important, of course, to prioritize study participants’ well-being.

“There clearly need to be safeguards in place,” Strassman says. “One would be the establishment of pre-arranged signals from the volunteer indicating that they wish to come out of the DMT state. In addition, there would need to be built in certain time and dose limits, which would automatically come into play in order to assure that the volunteer is doing all right.”

One exciting possibility of extending the duration is the ability to make MRI scans of the DMT-journeying brain for the first time. With teams at London’s Imperial College recently completing the first ever MRI brain scans involving LSD and psilocybin, it seems likely that DMT might follow…


About the Author
Jesse Jarnow is the author of Heads: A Biography of Psychedelic America (Da Capo, 2016). His most recent article for The Influence was “Seven Discoveries From 1960s Issues of ‘Micro-Gram,’ the Government’s Secretive Drugs Memo.” He tweets at @HeadsNewsand publishes the weekly Heads News bulletin.
**This article is re-printed here with permission from The Influence, a site covering the full spectrum of human relationships with drugs. Follow them on Facebook and on Twitter.**
%d bloggers like this: