What Is Mrsa?

Methicillin-resistant Staphylococcus aureus, or MRSA, is a strain of staph bacteria that is resistant to the antibiotics normally used to treat such infections.

In the 1940s, some 60 years after the discovery of the bacterium S. aureus, doctors began treating staph infections with penicillin. But the overuse and misuse of the drug helped the microbes evolve with resistance to penicillin by the 1950s.

Doctors then started using methicillin to counter the growing problem of penicillin-resistant staph infections, and the new drug quickly became the common treatment for S. aureus, according to the National Institute of Allergy and Infectious Diseases.

In 1961, British scientists discovered MRSA; the first case of this "superbug" in the United States occurred in 1968. Over time, strains of MRSA developed resistances to other penicillin-related antibiotics.

In fact, MRSA is now resistant to an entire class of penicillin-like antibiotics called beta-lactams, which includes amoxicillin, oxacillin, dicloxacillin and many others.

Experts used to think MRSA only affected people in health care settings, particularly patients with weakened immune systems or those who had recently undergone surgery. But in the 1990s, a different strain of MRSA emerged outside of the hospital. This "community-associated MRSA" predominantly affects people who are frequently in close, physical contact with others, such as athletes, inmates, soldiers and childcare workers.

Today it's quite common — and normal — to have staph bacteria on your skin or in your nose. Indeed, about one-third of the world's population have S. aureus bacteria on their bodies, and about 2 percent of people carry MRSA, according to the Centers for Disease Control and Prevention.

Usually, the staph on a person's skin doesn't cause an infection or disease symptoms, but problems can arise if the bacteria gets into the body. Staph skin infections start off as a small, red bump that resembles a spider bite — these infections can progress quickly, turning into swollen, painful abscesses, which doctors need to surgically drain.

If the bacteria burrow deeper, they can cause infections throughout the body, including in the bloodstream, heart, bones, joints, lungs and surgical wounds, which can result in chest pain, fever and even death.

As a last resort, life-threatening MRSA infections can still be treated with the antibiotic vancomycin. However, new treatments may eventually be needed, as a few cases of vancomycin-resistant S. aureushave already been reported.

Follow Joseph Castro on Twitter. Follow us @livescience, Facebook & Google+.

How Fast Do You Walk? Your Answer Could Predict Your Risk Of Heart Disease Death

A simple question — how fast do you walk? — may help researchers determine who has a higher risk of death from heart disease, a new study from the United Kingdom suggests.

The study found that middle-age adults who said they typically walk at a slow pace were about twice as likely to die from heart disease during the study period, compared with those who said they walk at a brisk pace. The findings held even after the researchers accounted for factors that could affect the results, such as people's exercise habits, their diets, and whether they smoked or drank alcohol.

The study suggests that "a simple, self-reported measure of slow walking pace" would help doctors determine people's risk of death from heart disease, the researchers wrote in the Aug. 21 issue of the European Heart Journal. [Top 10 Amazing Facts About Your Heart]

For the study, the researchers analyzed information from more than 420,000 middle-age adults in the United Kingdom, who were followed for about six years. None of the participants had heart disease at the time they entered the study. Participants were asked to rate their usual walking pace as "slow," "steady/average" or "brisk." The subjects also underwent an exercise test in a laboratory to determine their fitness levels.

During the study, nearly 8,600 of the participants died, and of these, about 1,650 died from heart disease.

People who said they were slow walkers were between 1.8 and 2.4 times more likely to die of heart disease during the six-year study period, compared with those who said they were brisk walkers. The risk was highest for those with a low body mass index (BMI), which could mean the individuals were malnourished or had high levels of muscle tissue loss with age (a condition known as sarcopenia), the researchers said.

The study also found that people's self-reported walking pace was strongly linked with their levels of physical fitness on the exercise test. In other words, a low fitness level among slow walkers could explain their higher risk of death from heart disease, the researchers said.

"Self-reported walking pace could be used to identify individuals who have low physical fitness" levels and, consequently, higher risk of death from heart disease, study co-author Tom Yates, of the University of Leicester in the United Kingdom, said in a statement. These individuals might benefit from interventions to improve their physical fitness, he said. However, more research is needed to examine the extent to which people's walking pace could be used to improve current predictors for risk of death by heart disease, the researches said.

The study also looked at whether walking pace was linked with people's risk of death from cancer, but it did not find a consistent link.

Original article on Live Science.

How Bad Is Second-hand Smoke?

This Week’s Question: I live with my 40-year-old son and he smokes like the proverbial chimney around the house. I’m afraid of what it’s doing to his health. What can I do to get him to quit?

Tell him he may be killing you with his secondhand smoke.

Secondhand smoke—also called environmental tobacco smoke (ETS)—is made up of  the “sidestream” smoke from the end of a cigarette, pipe, or cigar, and the “mainstream” smoke that is exhaled.

Nonsmokers exposed to secondhand smoke absorb the same 4,000 chemical compounds that smokers do. More than 60 of these compounds are known or suspected to cause cancer.

Each year, in the United States alone, secondhand smoke is responsible for about 40,000 deaths from heart disease, and about 3,000 lung-cancer deaths,

Secondhand smoke causes increased cardiovascular risks by damaging blood vessels, decreasing your ability to exercise and altering blood cholesterol levels.

Some research indicates that people exposed to a spouse's cigarette smoke for several decades are about 20 percent more likely to have lung cancer. Those who are exposed long-term to secondhand smoke in the workplace or social settings may increase their risk of lung cancer by about 25 percent.

Some of the components found in tobacco smoke that are known to cause cancer or are suspected to be carcinogenic include: formaldehyde, arsenic, cadmium, benzene and ethylene oxide.

Here are a few other chemicals in tobacco smoke along with their effects: ammonia (irritates lungs), carbon monoxide (hampers breathing),  methanol (toxic when inhaled)  and hydrogen cyanide (interferes with respiration).

Throughout the world, governments are taking action against smoking in public places, both indoors and outdoors. Smoking is either banned or restricted in public transportation. Several local communities have enacted nonsmokers’ rights laws, most of which are stricter than state laws.

Although air-conditioning may remove the visible smoke in your home, it can't remove the particles that continue to circulate and are hazardous to your health, so don’t delude yourself that running the AC is the answer to secondhand smoke dangers.

To solve your problem, you should try to get your son to seek help in fighting his addiction to nicotine. There are many programs available. Call your doctor for some recommendations. Meanwhile, for your own health, you should insist that he not smoke in your house.

The Healthy Geezer column publishes each Monday on LiveScience. If you would like to ask a question, please write fred@healthygeezer.com. © 2010 by Fred Cicetti.

Docs Cite Head Injuries In Ruling Out Youth Boxing

Children who box can suffer long-term damage or death from head injuries, especially concussions, so in a new policy statement, the American Academy of Pediatrics is saying the sport is not appropriate for children or teens.

Researchers from the AAP and the Canadian Paediatric Society reviewed the literature and found that a child's brain is more vulnerable to concussions than an adult's brain. Further, a child's brain can take longer to heal, and resulting memory impairment can make learning more difficult.

The two groups published the paper today (Aug. 29) in the journal Pediatrics. The paper reinforces an earlier position from the AAP, and echoes concerns about boxing from groups such as the American Medical Association and the British Medical Association.

While other sports such as football and ice hockey have higher injury rates in general, boxers "are actually rewarded for deliberate hits to the head and face," said study co-author Laura Purcell, a pediatric sport medicine physician at McMaster University in Hamilton, Ontario. "We needed to take a strong stand against boxing in youth athletes because of the risk of head injuries."

Indeed, studies of amateur and professional boxers show that more than 70 percent of boxing injuries were to the head.

Further, concussions accounted for one- third to one-half of injuries in amateur boxers, and 13 percent of matches ended because of concussions, Purcell said.

Second impact syndrome

Not only are children more susceptible to concussions, but repeated concussions also present the theoretical risk of a fatal condition called second impact syndrome, Purcell told MyHealthNewsDaily.

If children suffer a second concussion "before they've recovered, they can develop fatal brain swelling," she said. "Part of the problem may be that children are unaware that they've had a head injury, and therefore can't take the appropriate steps to protect themselves."

It's hard to argue against the authors' conclusions that brain trauma in children should be avoided, said Robert Cantu, a professor of neurosurgery at Boston University School of Medicine.

"It's not a good idea at any age," Cantu said. "But, we particularly don't want our youth to sustain head injuries." 

Part of the reason children are more susceptible to injury is that their brain cells are not fully myelinated, Cantu said. Myelin is an insulating material that forms around parts of brain cells.  Lacking myelin "makes the brain more susceptible to being injured when the brain is stretched or strained," he said.

In addition to brain vulnerabilities, children have weaker necks and proportionally bigger heads than adults. These differences increase the chance of a whiplash type of injury that can violently shake the brain, Cantu said.

The new policy seems less an indictment of boxing than a warning about all sports where head injury is common, Cantu said.

Still, there could be instances when the benefits of boxing outweigh the consequences, he said. "Boxing is largely participated in by a population that doesn't have access to ice hockey rinks and tennis courts," Cantu said. 

Add up the pluses and minuses

For that population, "it is much riskier to be out on the street than it is to be in a gym working out," he said.

"I think you add up all the pluses and the minuses and you try to encourage kids not to play these sports with a high risk of head injury."

Purcell said boxing simply isn't appropriate for children. "Our goal is to try to steer them to sports where the focus is not deliberate hits to the head and face," she said.

In the past, people have proposed banning blows to the head in youth boxing, an idea Cantu said has merit. "You'd get all the … musculoskeletal benefits out of boxing, but just eliminate the head trauma."

Pass it on: Children have a higher risk of problems associated with head injury, especially concussions, and doctors should steer kids away from boxing, a sport in which participants are rewarded for blows to the head and face.

This story was provided by MyHealthNewsDaily, a sister site to LiveScience. Follow MyHealthNewsDaily on Twitter @MyHealth_MHND. Find us on Facebook.

Science Of Disbelief: When Did Climate Change Become All About Politics?

Barely over a quarter of Americans know that almost all climate scientists agree that climate change is happening and that humans are to blame, a new Pew Research Center survey finds.

The survey also reveals a strong split between political liberals and political conservatives on the issue. While 55 percent of liberal Democrats say climate scientists are trustworthy, only 15 percent of conservative Republicans say the same.

The findings are in line with the results of other surveys of the politics of climate change, said Anthony Leiserowitz, director of the Yale Program on Climate Change Communication. Leiserowitz was not involved in the Pew study, but he and his colleagues conduct their own surveys on climate attitudes. [The Reality of Climate Change: 10 Myths Busted]

"The overwhelming finding that they see here is that there's a strong partisan divide on climate change, and that is a pattern we first saw emerge in 1997," Leiserowitz told Live Science.

The partisan gap isn't necessarily set in stone, however, Leiserowitz said. It's actually been narrowing recently — but it remains to be seen how the result of this year's presidential election may affect the divide. [The Reality of Climate Change: 10 Myths Busted]

Prior to 1997, the two major parties held similar beliefs on the occurrence of human-caused climate change, Leiserowitz said. Right around that time, then-President Bill Clinton and then-Vice President Al Gore took on the issue and pushed for the Kyoto Protocol, an international climate treaty meant to reduce greenhouse gas emissions.

"That's the moment when they come back and say, 'This is a global problem, and the U.S. needs to be part of the solution,' that the two parties begin to diverge," Leiserowitz said.

Since then, the American public's belief that climate change is real has fluctuated. Belief that climate change exists and that it's human-caused began to rise around 2004 and hit a peak around 2007, driven by media coverage of California's climate initiatives under Republican Gov. Arnold Schwarzenegger and the Hollywood film "The Day After Tomorrow," released in 2004. (Really: Leiserowitz's research found that Americans who saw the blockbuster were moved to think climate change is a problem. Al Gore's film "An Inconvenient Truth" was released in 2006 but was seen by far fewer people, Leiserowitz said.)

Research has shown that Americans who saw the 2004 blockbuster "The Day After Tomorrow" were moved to agree that climate change is a real issue.
Research has shown that Americans who saw the 2004 blockbuster “The Day After Tomorrow” were moved to agree that climate change is a real issue.

Credit: 2004 Twentieth Century Fox

These numbers waned during the 2008 recession, when the media abruptly stopped talking about climate change and the conservative tea-party wing of the Republican Party gained more power, Leiserowitz said. Belief in man-made climate change bottomed out in 2010 and 2011 but has been creeping upward since then, he said. [6 Unexpected Effects of Climate Change]

"That uptick is not coming from Democrats," he said. "Democrats have not really changed much at all. Independents — their belief that global warming is happening — has increased. But the real shift is happening among Republicans, and most interesting, the biggest shift — 19 percentage points — is among conservative Republicans."

But even with those increases, because the percentage of conservative Americans who believed in man-made climate change was so small, the overall proportion of conservatives who believe climate change is caused by human activity is still small. The new Pew survey, conducted between May 10 and June 6, 2016, found that 48 percent of Americans overall believe that the Earth is warming mostly because of human activity. Seventy-nine percent of liberal Democrats held that belief, compared with 63 percent of moderate Democrats, 34 percent of moderate Republicans and 15 percent of conservative Republicans.

Climate scientists have the trust of far more people on the left side of the political spectrum than the right. Only 9 percent of conservative Republicans believe that climate scientists' findings are usually influenced by the best available evidence, compared with 55 percent of liberal Democrats. Only 7 percent of conservative Republicans and 15 percent of moderate Republicans think climate scientists are motivated by concern for the public's best interest, compared with 31 percent of moderate Democrats and 41 percent of liberal Democrats.

Still, up until last spring, the trends were "moving in a more science-aligned direction," Leiserowitz said. Even members of the Republican establishment had been willing to discuss climate change as a problem, Leiserowitz said, citing former presidential candidate John McCain, who had sponsored and supported climate legislation in the U.S. Senate.

"Then, along comes Donald Trump, and he basically flips over all the card tables," Leiserowitz said. The candidate has called climate change a hoax on multiple occasions and once tweeted that "the concept of global warming was created by and for the Chinese in order to make U.S. manufacturing non-competitive." Trump has also been consistent in calling for less regulation of fossil fuel emissions. [Election Day 2016: A Guide to the When, Why, What and How]

"It's not clear where he has taken the Republican base," Leiserowitz said. The outcome of the election alone won't be enough to determine what kind of collateral damage climate opinion will accrue. Should Trump lose, Leiserowitz said, the Republican Party will have to decide whether to move even more rightward or whether to take a more centrist tack.

However, Americans' views aren't quite as extreme as the political class would make it seem, Leiserowitz said. Yale's surveys found that about 17 percent of Americans are alarmed about climate change, and 10 percent are entirely dismissive. The other 63 percent believe in, and are worried about, climate change to differing degrees.  

"Most Americans are actually in the middle, and more of those people in the middle are leaning pretty well toward the scientific consensus," Leiserowitz said. 

Original article on Live Science.

French Sperm Sinking, Not Swimming, Study Finds

French men's sperm concentration declined between 1989 and 2005, according to a new study that also finds fewer normally formed sperm in modern French semen.

The study is one of the largest to find a decline in sperm quality, a global concern. Anecdotal reports from some sperm banks, along with some scientific studies, mostly of developed countries, suggest that something may be wrong with these little swimmers. But with little good data from before 1950 and inconsistent measurements around the world, it's tough to know for sure whether sperm really is in decline.

The new study, published Wednesday (Dec. 4) in the journal Human Reproduction, has the advantage of including more than 26,600 men over a span of more than 15 years.

"To our knowledge, it is the first study concluding a severe and general decrease in sperm concentration and morphology at the scale of a whole country over a substantial period," the authors wrote. "This constitutes a serious public health warning. The link with the environment particularly needs to be determined."

Sperm count drop

The researchers examined sperm samples from men who visited fertility clinics because of their female partners' fertility problems. In other words, the men did not have fertility problems of their own.

Over the 17-year period, sperm concentration in semen dropped on average 32.2 percent, the researchers found, at a rate of about 1.9 percent each year. That translates to a drop from 73.6 million sperm per milliliter of semen in 1989 for an average 35-year-old man to 49.9 million sperm per milliliter in 2005. (A man with 15 million sperm per milliliter or higher has normal fertility, according to the World Health Organization.)

The number of healthy, properly shaped sperm also declined by 33.4 percent in the same time period, the study found. Part of that number may be due to advances in how sperm shape is measured, but improved technology can't explain the whole decline, the researchers said. [Sexy Swimmers: 7 Facts About Sperm]

Fertility questions

The results track with a 20-year-old British Medical Journal review that found sperm counts dropped by half between 1938 and 1990 in developed countries. Israeli sperm banks have reported turning away more men recently for poor sperm quality, though other countries, such as Denmark, have found no decreases in sperm counts or quality, according to studies done on their male populations.

The French results may not generalize to other nations, the researchers said, but they are cause for alarm. When a man has a count below 55 sperm cells per milliliter, it can take longer for that couple to conceive, study researcher Joëlle Le Moal, an environmental health epidemiologist at the Institut de Veille Sanitaire in Saint Maurice, France, said in a statement.

Environmental factors that influence sperm count may include endocrine-disrupting chemicals, which influence the body's hormones; epigenetic changes (changes not in the genome, but in the regulation of the genome, that can be passed down through generations); and obesity.

Le Moal said she hoped her research team's warning would promote research and monitoring of sperm counts on an international level. She and her team plan to implement a monitoring system at clinics in France, she said.

"Our example could help other countries to implement their own systems," Le Moal said. "International monitoring systems could be a good idea to understand what is happening on human reproductive outcomes around the world, and evaluate public health actions in [the] future."

Follow Stephanie Pappas on Twitter @sipappas or LiveScience @livescience. We're also on Facebook & Google+.

Bad Rap: Why B.o.b Is Wrong About A Flat Earth

A throwdown between a rapper and an astrophysicist centers on whether the Earth is a sphere, a scientific question that was supposedly settled in the third century B.C.

Rapper-singer Bobby Ray Simmons Jr. (known as B.o.B) released a track called "Flatline" on Monday (Jan. 25), dissing noted astrophysicist Neil deGrasse Tyson after the two had engaged in a Twitter argument over Earth's shape, which B.o.B purports to be flat. In the track, B.o.B hollers, "Aye, Neil Tyson need to loosen up his vest / They'll probably write that man one hell of a check," and even embeds part of a talk by Tyson in which he says, "So it's not actually a sphere, it's an … it's oblate, it's officially an oblate spheroid."

Earth's oblate spherical-ness was determined long ago. While the ancient Greeks were among the first to discern that the Earth is a sphere, there were still people who didn't think it could be true, because, well, look around. The ground is flat and plainly so all the way to the horizon. [Religion and Science: 6 Visions of Earth's Core]

This common-sense reasoning is, in part, what drives more modern flat-Earth beliefs. In the last century a whole society — the Flat Earth Society — has grown up around it. The 19th-century version was called the Zetetic Society, which eventually disbanded.

So what do flat-Earthers really believe? A look at the Flat Earth Society website gives some answers here. Their model of the Earth looks something like the logo of the United Nations, with the North Pole at the center. The Earth is a round disc, surrounded by an ice wall (Antarctica, which the U.N. logo doesn't show). The sun and moon are each about 32 miles across, and hang about 3,000 miles above the surface of the Earth.

Gravity doesn't enter into their argument, because flat-Earth cosmology says the whole disc is accelerating at exactly 32 feet per second in the "up" direction.

Earth's seeming flatness

There are several lines of evidence, though, that the Earth is round. But first, we can look at why it appears flat, and why that misled people for so long. [Earth from Above: 101 Stunning Images from Orbit]

The Earth is a sphere about 24,000 miles (38,624 kilometers) around at the equator — a pretty big number relative to a person's visual abilities. To calculate the distance one could expect to see, multiply the diameter of the Earth (about 7,917 miles, or 12,742 km) by the height of the person (or building, or mountain one is standing on) and take the square root. For a 6-foot-tall person standing on a beach, that works out to about 3 miles. (A more rough-and-ready version of this says the horizon in miles will be 1.22 times the square root of the height in feet.) This is also why the distance one can see gets larger the higher up you go.

This assumes a perfectly spherical Earth (it isn't) and no refraction of light from the atmosphere (there is some). But as a general estimate this works pretty well, and explains why the Earth looks flat: The "drop" on the horizon due to the planet's curvature is only a few feet per mile.

There are other lines of evidence, and that gets us to the ancient Greeks. Specifically, a man named Eratosthenes, who lived in Syene, Egypt. On the summer solstice, Eratosthenes had seen that a well had no shadows: the sun was at its zenith. He deduced that if the Earth were spherical, he could figure out the planet's size by checking the angle of the sun at some other location, assuming the sun was so far away that its rays were essentially parallel. So, in about 240 B.C., he had someone measure the distance between Syene (modern-day Aswan) and Alexandria, and checked the angle of the sun at both locations. He found a small, measurable difference in the angle, and calculated that the Earth was 24,662 to 28,968 miles in circumference, according to scientists today. He was wrong, but not by much.

By about A.D. 1, the idea of a spherical Earth was taken as a matter of course almost everywhere; Indian astronomers were convinced, and Islamic scholars used the concept to calculate the direction and distance to Mecca, according to the work of David A. King, a former professor of the history of science at Johann Wolfgang Goethe University in Berlin.

Even Christopher Columbus knew the Earth was round — the old story of him having to convince anyone otherwise is a myth (popularized by Washington Irving in a biography of Columbus). The real problem was that his estimates of the distance to China were too low. Contemporaries thought his mission was suicidal, because the crews would die of thirst absent stumbling on a hitherto unknown source of fresh water (as noted by Samuel Elliot Morrison, who wrote a Pulitzer-Prize winning biography of Columbus in 1942). Ferdinand Magellan, of course, killed the flat-Earth idea once and for all by sailing all the way around the world.

Flat-Earthers

The modern flat-Earthers can trace their intellectual lineage to a man named Samuel Rowbotham (1816–1884). He published a book on the flatness of the Earth called "Zetetic Astronomy: Earth Not a Globe." When he died those ideas lived on, as a woman named Lady Elizabeth Blount founded the Universal Zetetic Society. The society petered out after World War I. The current Flat Earth Society is headed by a man named Daniel Shenton, and has a website outlining experiments that purportedly show the Earth is flat.

One such experiment involves using a 6-mile length of canal to show that the Earth is not, in fact, round, disputing the old saw that ships' hulls disappear below the horizon and would not if the Earth were not curved. It's called the Bedford Level Experiment. A supporter of Rowbotham's used a telescope to observe a boat rowing away; since the hull of the boat remained visible even though it was 6 miles distant, it was initially taken to prove that the observation of ships' hulls was wrong, and a trick of perspective. The naturalist Alfred Russell Wallace repeated the experiment, and took into account the refraction of the atmosphere, by setting his sight line higher. He showed that, yes, in fact, the Earth is a sphere, as published in Nature in April 1870.

One other way to prove that there's a horizon is, in fact, with a good telescope. If the Earth were flat, then even if perspective made it hard to resolve objects near the horizon (it does), then with a decent telescope one should be able to see, for example, the Welsh coast from Boston. But you can't; no matter how good the telescope is, Europe never comes into view.

That aside, flat-Earthers have come up with some other — rather ingenious — "proofs" that the Earth is flat. One is the distances around the Southern Ocean. The flat-Earth model says that the distance between, say, Melbourne, Australia, and Santiago, Chile, should be greater than the distance between New York and Beijing. Melbourne is 7,002 miles (11,268 km) from Santiago, while New York is 6, 824 miles (10,982 km) from Beijing. Rowbotham gives some distance estimates in his book; the problem is they are just wrong: "From near Cape Horn, Chile to Port Philip in Melbourne, Australia the distance is 9,000 miles," Rowbotham writes. It's actually 5,681 miles. Rowbotham's figure would apply to a flat Earth, but he assumes that at the outset. Leaving the distance estimate aside, he assumes the longitudes are separated by 143 degrees; the actual figure is about 149 degrees.  

If the travel distance doesn't give Earth's curvature away, eclipses surely would: An interesting artifact of Eratosthenes' calculation is that if you assume the Earth is flat the figure for how high the sun would be matches the radius of the Earth — in this case, you assume that the sun's rays are not parallel (as Eratosthenes did) but are emanating from a spherical sun a short distance away. But the fact that eclipses happen gives the game away; if the planet were flat there would be nothing to cast a shadow, say, across the sun or moon. The Flat Earth Wiki says it's a "shadow object" and posits that the reason nobody has ever seen this behemoth object on Earth is that the sun's glare blots out everything else in the sky during the day. Plenty of people have observed Venus, for example, during the day (it's hard, but it can be done). If there were some shadow object big enough — remember flat-Earthers think the moon is some 32 miles across — it has to find a way to be invisible during both day and night. [See Photos: 'Lost' Astronomy Plates Show Historic Eclipse and More]

That links to another issue: The Pole Star gets lower in the sky as one travels south, and eventually dips below the horizon. If the Earth were flat no matter how far you went, Polaris would never get below the horizon at all, nor would new stars become visible as you traveled south – they certainly would not rise above the horizon at a constant rate of 1 degree for every degree of latitude traveled south, because of the geometry of a flat Earth, and flat sky.

Flat-Earthers assert precisely that, though: The stars are actually only 3,100 miles above us, and seeing Polaris approach the horizon is a trick of perspective. So as you travel south, more come into view. But were that the case, you would not see stars coming over a horizon; the southern stars would look bunched together in a kind of bright band that covered the southern sky — precisely because of perspective. (This assumes a flat sky as opposed to a dome shape, which is the only way the argument can work.)

According to flat-Earth cosmology, Antarctica is actually an ice wall that keeps the water in the oceans in place, and that NASA employees (among other government conspirators) are guarding the place to keep people out. Explorer Roald Amundsen was faking it (or badly mistaken), and clearly the dozens of expeditions to the region were all in on the conspiracy to hide the edges of the Earth, according to flat-Earth beliefs. The moon missions, by the way, are a hoax, and GPS satellites are rigged somehow to show the Earth is round, though it's unclear how they could stop anyone from flying or sailing in directions that would disprove that.

In addition, if the Earth were accelerating enough to produce the illusion of gravity, then eventually it would approach (but not quite reach) the speed of light, according to the theory of relativity. More interesting, the mass would continually increase (relative to the rest of the universe). But flat-Earth cosmology doesn't seem to include gravity, so it's also not clear whether they buy relativity at all. 

Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

Even Modest Exercise Boosts Self-image

Want to feel good about your self? Just get off the couch and do a little exercise. You don't even have to get real serious, a new study finds.

Heather Hausenblas of the University of Florida reviewed 57 intervention studies on the topic of exercise and how it makes people feel, and she concludes that "the simple act of exercise and not fitness itself can convince you that you look better," according to a statement released today by the university.

"You would think that if you become more fit that you would experience greater improvements in terms of body image, but that's not what we found," she said. "It may be that the requirements to receive the psychological benefits of exercise, including those relating to body image, differ substantially from the physical benefits."

The findings are detailed in the September issue of the Journal of Health Psychology.

As many as 60 percent of adults in national studies say they don't like the way their bodies look, Hausenblas said. And it's no secret that Americans spend billions of dollars a year for products designed to change their body size and shape, including diet pills and various cosmetic procedures.

"Body dissatisfaction is a huge problem in our society and is related to all sorts of negative behavior including yo-yo dieting, smoking, taking steroids and undergoing cosmetic surgery," she said. "It affects men and women and all ages, starting with kids who are as young as five years old saying they don't like how their bodies look."

The psychological advantages of exercise have been less explored, including the reduction of depression or confidence in body image, compared with the well-researched and understood physical benefits.

The study found no difference in body image improvement between people who met the American College of Sports Medicine guidelines by exercising at least 30 minutes a day five days a week and those who did not, Hausenblas said. The guidelines are considered the minimum amount of exercise needed to receive the health related benefits of physical activity, she said.

"We would have thought that people exercising this amount would have felt better about their bodies than those who did not work out as much," she said.

The study showed slightly larger benefits from exercise in terms of improving body image for women than men, Hausenblas said.

"We believed the gap would be much bigger, but what could be coming into play is the rise of body image issues among men," she said. "We're seeing more media portrayals of the ideal physique for men rather than the overriding emphasis on women we did in the past."

Also, older people were most likely to report enhanced body images from exercise, Hausenblas said. The gap may be explained by the older generation having more concerns about their body image than young people, who tend to exercise more, she said.

While the frequency of exercise mattered for boosting body perceptions, there were no differences for the duration, intensity, length or type of exercise, the study found.

"People who say they have high body dissatisfaction tend to exercise the least, so we wanted to take it a step further and see whether exercise causes people's body image to improve," she said.

"This is an important study because it shows that doing virtually any type of exercise, on a regular basis, can help people feel better about their bodies," said Kathleen Martin Ginis, a kinesiology professor at McMaster University in Ontario, Canada. "With such a large segment of the population dissatisfied with their physiques, it's encouraging to know that even short, frequent bouts of lower intensity exercise can improve body image."

Kinks Found In Ocean's 'conveyor Belt'

The water that fills the oceans doesn't stay in the same place from year to year — huge ocean-wide patterns of circulation slowly cycle that water around the world over the course of thousands of years.

Until now, oceanographers have subscribed to the overarching view that a conveyor belt-like system circulates the ocean waters from the poles to the equator and back again. Scientists have known that this was an oversimplification, and new research is showing where the ocean superhighway takes some unexpected twists and turns.

Scientists have found evidence that the ocean currents move on different pathways than previously thought, said M. Susan Lozier of Duke University in Durham, N.C., and author of a review of ocean circulation research detailed in the June 18 issue of the journal Science.

The basic global conveyor belt theory works like this: Warm surface water flows poleward from the tropics and cools, becoming denser and eventually sinking when it reaches the North Atlantic. The cooled water then returns along the bottom of the ocean to the tropics. It's this circulation that is thought to help redistribute heat around the planet.

"There's no doubt there is an overturning, we can see the evidence of it," said oceanographer Joshua Willis of NASA's Jet Propulsion Laboratory in Pasadena, Calif., who was not involved with the study. "We can actually measure it, but the details are very complicated. There's not a simple conveyor belt."

Recent research has shown that parts of the belt are interrupted by eddies — whirlpools of water that are several hundred kilometers in diameter. Also, winds have been revealed to play a larger role in overturning the waters.

Models now show that eddies can drive the recirculation of water on pathways other than the conveyor belt, Lozier said. Eddies in the Southern Ocean are one example of a terrific water mixer that influences other water masses, said Ronald Stouffer of the U.S. National Oceanic and Atmospheric Administration.

Having an accurate picture of the way the oceans' water moves around the planet is important because scientists say that it could be influenced by climate change. Because human-induced global warming seems to be increasing temperatures most rapidly at the poles, the air above the water will warm it up, preventing the water from cooling and sinking, which could cause a disruption to the ocean's circulation. Rethinking how the ocean's water mixes doesn't change this prediction; it helps scientists shine their flashlight on the areas where water mixing might slow down.

"Our new understanding gives us a better idea of how to — and where to — monitor the overturning," Lozier told OurAmazingPlanet.

Scientists plunk high-tech floats in the water and track their movements to understand the pathways of the upper and lower limbs of the world's ocean’s overturning. These measurements will aid assessments of the ocean’s role in the uptake, transport and storage of heat and carbon dioxide, all crucial components of Earth’s climate system.

"As the study of the modern ocean’s role in climate continues apace, the conveyor belt model no longer serves the community well — not because it is a gross oversimplification but because it ignores crucial structure and mechanics of the ocean’s intricate global overturning," Lozier wrote in her review.

Despite predictions that water mixing at the ends of the conveyor belt may slow down, there's no evidence that this is occurring, at least over the last five to 15 years, Willis said.

Low Vitamin D In Pregnancy Linked With Childhood Body Fat

Children of women who have low levels of vitamin D during pregnancy may have a higher risk of having more body fat during childhood, a new study from the UK suggests.

Researchers found that mothers who were deficient in vitamin Dtended to have children with more body fat at age 6, even when other factors were taken into account, such as a child’s exercise level or woman's weight gain during pregnancy.

"Our findings add weight to current concerns about the prevalence of low vitamin D status among women of reproductive age," said study researcher Siân Robinson, a principle research fellow at the University of Southampton.

The study showed an association, but does not suggest that low vitamin D levels during pregnancy cause high body fat in childhood, or obesity. More research must be done to better understand the role of a woman's vitamin D levels and her children's body fat.

The researchers surveyed 977 UK women during pregnancy, and tracked their children until age 6.

While the exact reason for the link is unclear, Robinson said that a woman's lack of vitamin D could have effects on a developing fetus that persist into childhood, and predispose him or her to gain excess body fat.

The study comes on the heels of growing concern over rising obesityand childhood obesity. Previous studies have suggested a link between vitamin D levels and body weight in children and adults, regardless of mother's levels during pregnancy, and vitamin D consumption is also a concern during infancy, the researchers said.

Young women in the UK tend to be deficient in vitamin D, and while they are encouraged to take supplements of the vitamin during pregnancy, this does not always happen, the researchers said.

The findings are part of a larger study in which researchers are analyzing the effects of pregnancy on long-term childhood development and growth.

The research was published today (May 24) in the American Journal of Critical Nutrition.

Pass it on: Not getting enough vitamin D during pregnancy might cause your baby to gain more body fat as a child.

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