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Math

Big Talk About Small Samples 243

Posted by samzenpus
from the read-all-about-it dept.
Bennett Haselton writes: My last article garnered some objections from readers saying that the sample sizes were too small to draw meaningful conclusions. (36 out of 47 survey-takers, or 77%, said that a picture of a black woman breast-feeding was inappropriate; while in a different group, 38 out of 54 survey-takers, or 70%, said that a picture of a white woman breast-feeding was inappropriate in the same context.) My conclusion was that, even on the basis of a relatively small sample, the evidence was strongly against a "huge" gap in the rates at which the surveyed population would consider the two pictures to be inappropriate. I stand by that, but it's worth presenting the math to support that conclusion, because I think the surveys are valuable tools when you understand what you can and cannot demonstrate with a small sample. (Basically, a small sample can present only weak evidence as to what the population average is, but you can confidently demonstrate what it is not.) Keep reading to see what Bennett has to say.
Space

Magnetic Field In Meteorite Provides Clues About Formation of Solar System 26

Posted by samzenpus
from the in-the-beginning dept.
An anonymous reader writes Scientists have discovered a meteorite that provides evidence that intense magnetic fields caused the formation of the solar system. A meteorite called Semarkona crashed in northern India in 1940 and is now being studied for signs of primordial magnetic fields. Lead researcher, Roger Fu, a planetary scientist at MIT says: "It's a very primitive meteorite, which means that since it formed about 4.5 billion years ago, not much has happened to it, this means it preserves the properties it had when it first formed, helping shed light on that time." From the article: "This meteorite is made up of mostly tiny round pellets known as chondrules, which formed droplets that quickly cooled in space. According to the study, the scientists focused on these chondrules that possessed iron-bearing minerals, known as dusty olivine crystals, and if they appeared to have a magnetic field present while they were cooling, then the magnetic properties of these crystals might have recorded the strength of the magnetic fields."
Space

Leonid Meteor Shower Hits Tonight, Peaks Tomorrow 20

Posted by timothy
from the prepare-for-mere-whelming dept.
Though expectations for a spectacular show may be low, the Leonid meteor shower is on the way. For those in the continental U.S., late Monday night into Tuesday early morning will be your best chance to catch a few glimpses. Space.com explains why you might see only a smattering of meteors: This year finds Comet Tempel-Tuttle nearing the far end of its elongated orbit. In 2010, the comet crossed the orbit of Uranus and in 2016 it will be as far from the sun as it can get: 1.84 billion miles (2.96 billion km). That's not only where the comet is, but also where the heaviest concentrations of meteoroids are as well. In contrast, at the point in the comet's orbit where we will be passing by on Tuesday morning, there is nothing save for a scattered few particles; stragglers likely loosed from the comet's nucleus a millennium or two ago. So the 2014 Leonids are expected to show only low activity this year; "maybe" at best 5 to 10 Leonids per hour might be seen.
Science

Scientists Discover Diamond Nanothreads 78

Posted by timothy
from the this-nanoring-shows-how-much-I-care dept.
First time accepted submitter sokol815 writes Penn State University scientists discovered diamond nanothreads can be created from benzene when compressed. The compression brings the benzene molecules into a highly reactive state. It was expected that the molecules would create a non-ordered glass-like material, but due to the slow speed of decompression used, the benzene molecules ordered themselves into a naturally repeating crystal. The experiment took place at room-temperature. Early results indicate that these nanothreads are stronger than previously produced carbon nanotubes, and may have applications throughout the engineering industry.
Space

After Four Days, Philae Team Gets to Rest 87

Posted by timothy
from the beating-god-by-three-full-days dept.
The Associated Press reports on one happy consequence of the inevitable shutdown of the Philae lander, after its incredible landing on Rosetta: the team that was in control of the lander here on earth finally gets to take a well-deserved break, after four nearly sleepless days and nights. It seems unlikely -- though it's not impossible -- that Philae will get enough solar energy to briefly wake up again; its bouncy landing and harpoon malfunction mean that the craft is in shadow rather than the sunlight that it was hoped to bask in. From CNN: Originally, it was supposed to have seven hours of light per comet day -- which lasts just 12.4 hours. Now it is exposed only 1.5 hours a day. That's likely not enough to juice up Philae's rechargeable secondary battery, ESA said. There is one last hope. "Mission controllers sent commands to rotate the lander's main body, to which the solar panels are fixed," ESA says in on its blog. "This may have exposed more panel area to sunlight."
Medicine

Machine Learning Used To Predict Military Suicides 74

Posted by timothy
from the sobering-statistics dept.
HughPickens.com (3830033) writes David Wagner writes that a predictive computer model using machine learning methods is helping to identify soldiers in the United States Army most likely to commit suicide. Computers combed through data on more than 40,000 soldiers who'd been hospitalized for mental health problems looking at 421 variables on each soldier drawn from 38 military data systems. Using a method known as "machine learning," the researchers identified roughly two dozen factors that are most important in predicting soldiers most likely to commit suicide. The soldiers most likely to take their own lives were men with past suicidal behavior and a history of psychiatric disorders and criminal offenses, including weapons possession and verbal assaults. Soldiers with hearing loss also faced heightened risk — a strong indicator that they had suffered a head injury. So did enlisting in the Army after age 27, most likely because those soldiers had already experienced trouble finding their way in life. "There's this group that comes to the Army later in life — they're smart, they have skills, they tend not to be married and they have no career or have left a career to join," Dr. Kessler said. "We don't know why they should be at higher risk, but they appear to be."

Murray Stein, co-author of the new study, found that among soldiers recently discharged from psychiatric hospitals, more than half of suicides were committed by just five percent of patients. "The most impressive thing is that they identified this high-risk group in the hospital, and by just focusing on one in 20 of them, you're really dramatically improving your ability to predict," says Dr. Mark Olfson, a professor of psychiatry at Columbia University who was not involved in the study. "Clinicians don't do a very good job predicting suicide risk, even though we think we do."
Medicine

How To Anesthetize an Octopus 105

Posted by timothy
from the calm-as-calamari dept.
sciencehabit writes Researchers have figured out how to anesthetize octopuses so the animals do not feel pain while being transported and handled during scientific experiments. In a study published online this month in the Journal of Aquatic Animal Health, researchers report immersing 10 specimens of the common octopus in seawater with isoflurane, an anesthetic used in humans. They gradually increased the concentration of the substance from 0.5% to 2%. The investigators found that the animals lost the ability to respond to touch and their color paled, which means that their normal motor coordination of color regulation by the brain was lost, concluding that the animals were indeed anesthetized. The octopuses then recovered from the anesthesia within 40 to 60 minutes of being immersed in fresh seawater without the anesthetic, as they were able to respond to touch again and their color was back to normal.
Space

Philae's Batteries Have Drained; Comet Lander Sleeps 336

Posted by timothy
from the amazing-feats-done-dirt-dirt-cheap dept.
astroengine (1577233) writes "In the final hours, Philae's science team hurried to squeeze as much science out of the small lander as possible. But the deep sleep was inevitable, Rosetta's lander has slipped into hibernation after running its batteries dry. This may be the end of Philae's short and trailblazing mission on the surface of Comet 67P, but a huge amount of data — including data from a drilling operation that, apparently, was carried out despite concerns that Philae wasn't positioned correctly — was streamed to Rosetta mission control. "Prior to falling silent, the lander was able to transmit all science data gathered during the First Science Sequence," said Stephan Ulamec, Philae Lander Manager. "This machine performed magnificently under tough conditions, and we can be fully proud of the incredible scientific success Philae has delivered.""
Earth

How To Mathematically Predict Lightning Strikes 41

Posted by timothy
from the out-standing-in-his-field dept.
rossgneumann writes Soon, it's very possible that when you say something like "you have better odds of being struck by lightning," that won't necessarily mean it's all that rare. And there's a good chance that you'll be able to tell that person (roughly) what the odds of that happening are. Research published this week in Nature provides an equation that is reasonably accurate at mathematically predicting lightning strikes. From the article: "There's not a whole lot of noise in Romps's estimates: CAPE [Convective Available Potential Energy] is something that can be predicted out fairly easily: "All [models] in our ensemble predict that [the United State's] mean CAPE will increase over the 21st century, with a mean increase of 11.2 percent per degree Celsius of global warming," he wrote. "Overall, the [models] predict a ~50 percent increase in the rate of lightning strikes in the United States over the 21st century."
Medicine

Researchers Develop $60 Sonar Watch To Aid the Visually Impaired 30

Posted by samzenpus
from the daredevil-watch dept.
Taffykay writes Biology and computer science students and professors at Wake Forest University have teamed up to develop a device to assist the visually impaired. Following the principles of echolocation used by bats and moths, the interdisciplinary team has developed a watch-like unit that allows the wearer to navigate their environment using sonar. To make the project even more remarkable, all the parts and materials for the prototype cost less than $60.
Space

Boeing Readies For First Ever Conjoined Satellite Launch 67

Posted by samzenpus
from the two-by-two dept.
Zothecula writes Boeing has successfully joined two of its 702SP satellites in a stacked configuration in preparation for a launch scheduled for early 2015. Aside from being the first involving conjoined satellites, the launch will also put the first satellites to enter service boasting an all-electric propulsion system into orbit. "Designed by Boeing Network & Space Systems and its defense and security advanced prototyping arm, Phantom Works, the 702SP (small platform) satellites are an evolution of the company's 702 satellite. Operating in the low- to mid-power ranges of 3 to 9 kW, instead of chemical propulsion, the satellites boast an all-electric propulsion system that Boeing says minimizes the mass of the spacecraft and maximizes payload capacity."
Math

Mathematics Great Alexander Grothendieck Dies At 86 49

Posted by samzenpus
from the rest-in-peace dept.
An anonymous reader writes Alexander Grothendieck, one of the great eccentric geniuses of 20th century mathematics, has died in France at the age of 86. Grothendieck was the leading mind behind algebraic geometry. He was awarded the Fields Medal in 1966. He reached the very pinnacle of his profession before abandoning the discipline, taking up anti-war activism, retreating into the life of a recluse and refusing to share his research. He died on Thursday in a hospital in Saint-Girons in southwestern France.
Education

Education Chief Should Know About PLATO and the History of Online CS Education 134

Posted by samzenpus
from the back-in-the-day dept.
theodp writes Writing in Vanity Fair, U.S. Secretary of Education Arne Duncan marvels that his kids can learn to code online at their own pace thanks to "free" lessons from Khan Academy, which Duncan credits for "changing the way my kids learn" (Duncan calls out his kids' grade school for not offering coding). The 50-year-old Duncan, who complained last December that he "didn't have the opportunity to learn computer skills" while growing up attending the Univ. of Chicago Lab Schools and Yale, may be surprised to learn that the University of Illinois was teaching kids how to program online in the '70s with its PLATO system, and it didn't look all that different from what Khan Academy came up with for his kids 40 years later (Roger Ebert remarked in his 2011 TED Talk that seeing Khan Academy gave him a flashback to the PLATO system he reported on in the '60s). So, does it matter if the nation's education chief — who presides over a budget that includes $69 billion in discretionary spending — is clueless about The Hidden History of Ed-Tech? Some think so. "We can't move forward," Hack Education's Audrey Watters writes, "til we reconcile where we've been before." So, if Duncan doesn't want to shell out $200 to read a 40-year-old academic paper on the subject (that's a different problem!) to bring himself up to speed, he presumably can check out the free offerings at Ed.gov. A 1975 paper on Interactive Systems for Education, for instance, notes that 650 students were learning programming on PLATO during the Spring '75 semester, not bad considering that Khan Academy is boasting that it "helped over 2000 girls learn to code" in 2014 (after luring their teachers with funding from a $1,000,000 Google Award). Even young techies might be impressed by the extent of PLATO's circa-1975 online CS offerings, from lessons on data structures and numerical analysis to compilers, including BASIC, PL/I, SNOBOL, APL, and even good-old COBOL.
Power

Comet Probe Philae To Deploy Drill As Battery Life Wanes 223

Posted by samzenpus
from the last-days dept.
An anonymous reader writes With less than a day of battery life left, The European Space Agency's Philae probe will begin to drill for samples even though the drilling may dislodge it. From the article: "Philae is sitting in the shadow of a cliff, and will not get enough sunlight to work beyond Saturday. Friday night's radio contact with the orbiting Rosetta satellite will be the last that engineers have a reasonable confidence will work. The team is still not sure where on the surface the probe came to rest after bouncing upon landing on Wednesday. Scientists have been examining radio transmissions between the orbiter and the lander to see if they can triangulate a position. This work has now produced a 'circle of uncertainty' within which Philae almost certainly lies."
Wikipedia

Researchers Forecast the Spread of Diseases Using Wikipedia 61

Posted by samzenpus
from the searching-sick dept.
An anonymous reader writes Scientists from Los Alamos National Laboratory have used Wikipedia logs as a data source for forecasting disease spread. The team was able to successfully monitor influenza in the United States, Poland, Japan, and Thailand, dengue fever in Brazil and Thailand, and tuberculosis in China and Thailand. The team was also able to forecast all but one of these, tuberculosis in China, at least 28 days in advance.
Space

Thanks To the Private Space Industry, Things Are Looking Up For Space City USA 47

Posted by samzenpus
from the not-dead-yet dept.
gallifreyan99 writes When the shuttle program was ended, and manned space exploration was put on hold, the people of Titusville, Florida were left in big trouble. "Just 20 miles northwest of Kennedy Space Center in Florida, it used to have a proud nickname: Space City USA. The dizzying boom of the 1950s and '60s helped create myriad jobs by giving work to nearby aerospace companies. Unfortunately, the past 15 years have seen everything dry up By December 2010, Titusville had one of the America's highest unemployment rates, 13.8 percent." But even though there's been plenty of bad news recently, the city hopes that the private space industry can save it from destruction.
Biotech

Researchers Use DNA To Record a Cell's Life History 48

Posted by samzenpus
from the what-have-you-done? dept.
sciencehabit writes If cells could talk, they'd have quite a story to tell: Their life history would include what molecules they'd seen passing by, which signals they'd sent to neighbors, and how they'd grown and changed. Researchers haven't quite given cells a voice, but they have now furnished them with a memory of sorts—one that's designed to record bits of their life history over the span of several weeks. The new method uses strands of DNA to store the data in a way that scientists can then read. Eventually, it could turn cells into environmental sensors, enabling them to report on their exposure to particular chemicals, among other applications.
Communications

SatNOGS Wins the 2014 Hackaday Prize For Satellite Networked Open Ground Station 21

Posted by samzenpus
from the king-of-the-hill dept.
szczys writes SatNOGS has won the 2014 Hackaday Prize. The team of developers designed a satellite ground station which can be built with available tools, commodity parts, and modest skills. Data from each station can be shared via a networked protocol to benefit a much wider swath of humanity than one station could otherwise accomplish.
Power

Comet Probe Philae Unanchored But Stable — And Sending Back Images 132

Posted by timothy
from the overengineering-is-the-best-kind dept.
An anonymous reader writes with an update to the successful landing of the ESA's comet probe Philae, which (as mentioned yesterday) had problems attaching to the surface of the comet's Rosetta: "BBC now reports that Philae is stable on the surface. Although no source claims so, we can all imagine a faint humming of 'Still Alive' coming from the probe." Not just stable, but sending pictures while it can. From the article: The probe left Rosetta with 60-plus hours of battery life, and will need at some point to charge up with its solar panels. But early reports indicate that in its present position, the robot is receiving only one-and-a-half hours of sunlight during every 12-hour rotation of the comet. This will not be enough to sustain operations. As a consequence, controllers here are discussing using one of Philae's deployable instruments to try to launch the probe upwards and away to a better location. But this would be a last-resort option. New submitter Thanshin notes that the persistent Philae bounced a few times, and actually performed 3 landings, at 15:33, 17:26 & 17:33 UTC.Thanshin adds links to a handful of relevant Twitter feeds, if you want to follow in something close to real time: Philae2014; esa_rosetta; and Philae_MUPUS (MUlti PUrpose Sensor One).
Biotech

How 4H Is Helping Big Ag Take Over Africa 377

Posted by samzenpus
from the white-elephant dept.
Lasrick writes 4H is in Africa, helping to distribute Big Ag products like DuPont's Pioneer seeds through ostensibly good works aimed at youth. In Africa, where the need to produce more food is especially urgent, DuPont Pioneer and other huge corporations have made major investments. But there are drawbacks: "DuPont's nutritious, high-yielding, and drought-tolerant hybrid seed costs 10 times as much. While Ghanaians typically save their own seeds to plant the next year, hybrid seeds get weaker by the generation; each planting requires another round of purchasing. What's more, says Devlin Kuyek, a researcher with the sustainable-farming nonprofit Genetic Resources Action International, because hybrid seeds are bred for intensive agriculture, they typically need chemicals to thrive."

The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka!" (I found it!) but "That's funny ..." -- Isaac Asimov

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