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Scientists Say Walking Burns More Calories Than Previously Thought

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Step-counters, rejoice: physiologists have found that the equations used for calculating energy expenditure are inaccurate, and say we’re likely burning more calories walking than we realized. They published their report in the Journal of Applied Physiology. 

Today, most programs use one of two methods to estimate calories burned by walkers: the ACSM (for the American College of Sports Medicine) and the Pandolf, which was invented by the military. These equations are about 40 years old, which is reason enough to test them again. They were also developed using just a few adult men of average height, and if we’ve learned anything in the last few years, it’s that a small group of adult men cannot be used as a stand-in for the entire population.

So Southern Methodist University (SMU) physiologists Lindsay Ludlow and Peter Weyand decided it was time to put these formulas to the test. "Burning calories is of major importance to health, fitness and the body's physiological status," Weyand said in a press statement. "But it hasn't been really clear just how accurate the existing standards are under level conditions because previous assessments by other researchers were more limited in scope." 

The researchers built a database of existing data in the scientific literature. With this data, they could compare the ACSM, Pandolf, and other standard equations. They found that for people walking on firm, level ground, both the ACSM and Pandolf underestimated calories burned in 97 percent of the cases examined by researchers. Clearly, a new equation was in order. 

Ludlow and Weyand set out to create an algorithm that would work for anyone. "The SMU approach improves upon the existing standards by including different-sized individuals and drawing on a larger database for equation formulation," Weyand said. 

Dr. Ludlow monitors a colleague during a treadmill test. Image Credit: Hillsman Jackson, SMU

If you want to play along at home (in your ... home physiology lab), here’s what they came up with:

(VO2 is oxygen consumption and Ht is height measured in meters.)

Ludlow said their equation should apply “…regardless of the height, weight, and speed of the walker. And it’s appreciably more accurate.”  

A lot more accurate, in fact (not that that’s a high bar). The new equation is four times more accurate when used to calculate energy expenditure of a mixed group of adults and kids. For adults alone, it’s still two to three times more accurate than the old formulas. 

Accurate accounting of energy expenditure is important for more than just casual walkers. Once a person’s estimated calorie-burn rate has been established, the formula can be used to predict how much energy that person will use—and therefore how much they will need—for a certain task. Such an algorithm could be useful for athletes in training, but also for military operations, in which the need for physiological efficiency is at a premium.

"These soldiers carry incredible loadsup to 150 pounds, but they often need to be mobile to successfully carry out their missions," Weyand said. In other words, they've got to be taking in enough calories to get the job done.

As yet, the formula has only been tested for walkers on solid, flat ground. The researchers’ next step is to expand the algorithm to calculate calorie burning on hills. 

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More Details Emerge About 'Oumuamua, Earth's First-Recorded Interstellar Visitor
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In October, scientists using the University of Hawaii's Pan-STARRS 1 telescope sighted something extraordinary: Earth's first confirmed interstellar visitor. Originally called A/2017 U1, the once-mysterious object has a new name—'Oumuamua, according to Scientific American—and researchers continue to learn more about its physical properties. Now, a team from the University of Hawaii's Institute of Astronomy has published a detailed report of what they know so far in Nature.

Fittingly, "'Oumuamua" is Hawaiian for "a messenger from afar arriving first." 'Oumuamua's astronomical designation is 1I/2017 U1. The "I" in 1I/2017 stands for "interstellar." Until now, objects similar to 'Oumuamua were always given "C" and "A" names, which stand for either comet or asteroid. New observations have researchers concluding that 'Oumuamua is unusual for more than its far-flung origins.

It's a cigar-shaped object 10 times longer than it is wide, stretching to a half-mile long. It's also reddish in color, and is similar in some ways to some asteroids in own solar system, the BBC reports. But it's much faster, zipping through our system, and has a totally different orbit from any of those objects.

After initial indecision about whether the object was a comet or an asteroid, the researchers now believe it's an asteroid. Long ago, it might have hurtled from an unknown star system into our own.

'Oumuamua may provide astronomers with new insights into how stars and planets form. The 750,000 asteroids we know of are leftovers from the formation of our solar system, trapped by the Sun's gravity. But what if, billions of years ago, other objects escaped? 'Oumuamua shows us that it's possible; perhaps there are bits and pieces from the early years of our solar system currently visiting other stars.

The researchers say it's surprising that 'Oumuamua is an asteroid instead of a comet, given that in the Oort Cloud—an icy bubble of debris thought to surround our solar system—comets are predicted to outnumber asteroids 200 to 1 and perhaps even as high as 10,000 to 1. If our own solar system is any indication, it's more likely that a comet would take off before an asteroid would.

So where did 'Oumuamua come from? That's still unknown. It's possible it could've been bumped into our realm by a close encounter with a planet—either a smaller, nearby one, or a larger, farther one. If that's the case, the planet remains to be discovered. They believe it's more likely that 'Oumuamua was ejected from a young stellar system, location unknown. And yet, they write, "the possibility that 'Oumuamua has been orbiting the galaxy for billions of years cannot be ruled out."

As for where it's headed, The Atlantic's Marina Koren notes, "It will pass the orbit of Jupiter next May, then Neptune in 2022, and Pluto in 2024. By 2025, it will coast beyond the outer edge of the Kuiper Belt, a field of icy and rocky objects."

Last week, University of Wisconsin–Madison astronomer Ralf Kotulla and scientists from UCLA and the National Optical Astronomy Observatory (NOAO) used the WIYN Telescope on Kitt Peak, Arizona, to take some of the first pictures of 'Oumuamua. You can check them out below.

Images of an interloper from beyond the solar system — an asteroid or a comet — were captured on Oct. 27 by the 3.5-meter WIYN Telescope on Kitt Peak, Ariz.
Images of 'Oumuamua—an asteroid or a comet—were captured on October 27.
WIYN OBSERVATORY/RALF KOTULLA

U1 spotted whizzing through the Solar System in images taken with the WIYN telescope. The faint streaks are background stars. The green circles highlight the position of U1 in each image. In these images U1 is about 10 million times fainter than the faint
The green circles highlight the position of U1 in each image against faint streaks of background stars. In these images, U1 is about 10 million times fainter than the faintest visible stars.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF

Color image of U1, compiled from observations taken through filters centered at 4750A, 6250A, and 7500A.
Color image of U1.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF

Editor's note: This story has been updated.

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Scientists Analyze the Moods of 90,000 Songs Based on Music and Lyrics
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Based on the first few seconds of a song, the part before the vocalist starts singing, you can judge whether the lyrics are more likely to detail a night of partying or a devastating breakup. The fact that musical structures can evoke certain emotions just as strongly as words can isn't a secret. But scientists now have a better idea of which language gets paired with which chords, according to their paper published in Royal Society Open Science.

For their study, researchers from Indiana University downloaded 90,000 songs from Ultimate Guitar, a site that allows users to upload the lyrics and chords from popular songs for musicians to reference. Next, they pulled data from labMT, which crowd-sources the emotional valence (positive and negative connotations) of words. They referred to the music recognition site Gracenote to determine where and when each song was produced.

Their new method for analyzing the relationship between music and lyrics confirmed long-held knowledge: that minor chords are associated with sad feelings and major chords with happy ones. Words with a negative valence, like "pain," "die," and "lost," are all more likely to fall on the minor side of the spectrum.

But outside of major chords, the researchers found that high-valence words tend to show up in a surprising place: seventh chords. These chords contain four notes at a time and can be played in both the major and minor keys. The lyrics associated with these chords are positive all around, but their mood varies slightly depending on the type of seventh. Dominant seventh chords, for example, are often paired with terms of endearment, like "baby", or "sweet." With minor seventh chords, the words "life" and "god" are overrepresented.

Using their data, the researchers also looked at how lyric and chord valence differs between genres, regions, and eras. Sixties rock ranks highest in terms of positivity while punk and metal occupy the bottom slots. As for geography, Scandinavia (think Norwegian death metal) produces the dreariest music while songs from Asia (like K-Pop) are the happiest. So if you're looking for a song to boost your mood, we suggest digging up some Asian rock music from the 1960s, and make sure it's heavy on the seventh chords.

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