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What's Up With "10-4" And Other Radio Lingo?

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Reader and frequent question-asker Nate J. wrote in wondering why we say things like "10-4" and "Roger" on walkie-talkies and other two-way radios.

The Ten-Codes

The ten-codes or ten-signals are code words used as stand-ins for common phrases in radio communication. Charles Hopper, a communications director with the Illinois State Police, developed them in 1937 to combat the problem of the first syllables or words of a transmission being cut off or misunderstood. Preceding every code with "ten" gave the sometimes slow equipment time to warm up and improved the likelihood that a listener would understand the important part of a message. The codes also allowed for brevity and standardization in radio message traffic.

The codes were expanded by the Association of Public-Safety Communications Officials-International (APCO) in 1974 and were used by both law enforcement agencies and civilian CB radio users. Over time, differing meanings for the codes came about in different agencies and jurisdictions, undoing the codes' usefulness as a concise and standardized system. The problem came to a head in 2005 during rescue operations after Hurricane Katrina. After several instances of inter-agency communication problems, the United States Federal Emergency Management Agency (FEMA) discouraged the use of ten-codes and today the federal government recommends they be replaced with plain, everyday language. Here's the official APCO list.

Roger That

In the days of the telegraph, the Morse code letter R (dot-dash-dot) was sometimes used to indicate "received" or "message received/understood." When radio voice communication began to replace telegraphs, Roger, the code word assigned to the letter R in the Joint Army/Navy Phonetic Alphabet (the radio alphabet used by all branches of the United States military from 1941 to 1956), took on the same role.

Contrary to what Hollywood would have you think, Roger only means "last transmission received/understood" and does not also mean or imply "I will comply." Wilco (Will Comply) is the code used if the speaker intends to convey "message received and will comply." Given that, the phrase Roger Wilco, which you so often hear in the movies, is redundant and not really used since Wilco alone covers all the bases and acknowledges receipt of message and states intent to comply.

Mayday


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Mayday is an international code word used to signal life-threatening emergencies. It was originated in 1923 by Frederick Stanley Mockford, a senior radio officer at London's Croydon Airport. He was given the task of coming up with a unique and easily understandable emergency code word. Most of the air traffic at Croydon was either coming from or going to Le Bourget Airport in Paris, so Mockford chose mayday because of its similarity to the French m'aider ("come help me").

Because it is an emergency signal, there are plenty of rules governing the use and format of a mayday call. A mayday call can only be made when life or craft is in imminent danger of death or destruction (and, as with fake 9-1-1 calls, fake mayday calls are considered serious crimes. In the U.S., making a fake distress call is a federal crime that can carry large fines and jail time), and once one is made, no other messages can be transmitted except to assist in the emergency.

Correct format for a Mayday call is:

- "Mayday, Mayday, Mayday." The call is always given three times in a row to keep it from being mistaken for a similar-sounding phrase, or to distinguish an actual distress signal from a message about a mayday call.

- "This is ____." The vessel name is repeated three times, followed by call sign if available.

- "Mayday. [vessel name]."

- "My position is ____." Position is given in latitude-longitude coordinates, or bearing and distance from a fixed point.

- "I am _____." The type of emergency, e.g. fire or sinking.

- "I require immediate assistance."

- "I have _____." The number of people on board and their condition, as well as any other pertinent information, e.g. abandoning to life rafts.

- "Over."

Some radio instructors suggest the mnemonic MIPDANIO for learning mayday signal format: Mayday, Identify, Position, Distress, Assistance, Number of crew, Information, Over.

Phonetic or Spelling Alphabets

The problem: a lot of letters sound alike. If two people are talking to each other on the telephone or a two-way radio, an "N" might be misheard as an "M," or a "B" might be heard as a "D," "T," or "C." If one person tells the other that the secret code that must be entered to save the world from imminent disaster is "M-A-T-T", there's a chance that we might all die because a little bit of static could cause the code to be heard as "N-8-B-D."

The solution: a phonetic alphabet or spelling alphabet, where code words are assigned to the letters of the alphabet acrophonically (that is, the code word assigned to a given letter starts with that letter, like Alpha for "A"). Using the Joint Army/Navy Phonetic Alphabet mentioned earlier, the above code becomes "Mike-Able-Tare-Tare" which is a little harder to mishear.

Today, the most commonly used spelling alphabet is the International Radiotelephony Spelling Alphabet. The alphabet was developed by the International Air Transport Association (IATA) and International Civil Aviation Organization (ICAO) after World War II and later adopted by organizations like International Maritime Organization (IMO), the Federal Aviation Administration (FAA), the American Radio Relay League (ARRL), and the North Atlantic Treaty Organization (NATO) (whose use of the alphabet led to its global spread and use of the common name, NATO phonetic alphabet).

In addition to these (and other) organizations, the alphabet is used by the military and in civilian industries (retail, IT and airlines for instance). The alphabet in its current form is:
Alfa
Bravo
Charlie
Delta
Echo
Foxtrot
Golf
Hotel
India
Juliet
Kilo
Lima
Mike
November
Oscar
Papa
Quebec
Romeo
Sierra
Tango
Uniform
Victor
Whiskey
X-ray
Yankee
Zulu.

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Big Questions
Why Do Small Dogs Live Longer Than Large Dogs?
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Why do small dogs live longer than large dogs?

Adriana Heguy:

The issue of body size and lifespan is a fascinating topic in biology. It’s strange that across species, at least in mammals, large-bodied animals live longer than small-sized animals. For example, elephants live a lot longer than mice. The theory is that
bigger animals have slower metabolisms than small animals, and that faster metabolisms result in more accumulation of free radicals that damage tissue and DNA. But this doesn't always hold for all animals and the “rate of living” theory is not widely accepted. What we cannot clearly understand remains fascinating.

But now if we look at within a given species, lifespan and body size are inversely correlated. This is definitively the case for dogs and mice, and it has been proposed that this is the case for humans, too. Why would this be? A possible explanation is that larger dogs (or mice, or people) grow faster than their smaller counterparts because they reach a larger size in more or less the same time, and that faster growth could be correlated with higher cancer rates.

We do not have a clear understanding of why growing faster leads to accelerated aging. But it seems that it is an accelerated rate of aging, or senescence, that causes larger dogs to have shorter lifespans than little dogs.

The figure above is from Ageing: It’s a Dog’s Life. The data is from 32 breeds. Note that the inverse correlation is pretty good, however some large dog breeds, at around 40 to 50 kg (or about 88 to 110 pounds), live 12 or 13 years in average while some other dog breeds of equal body size live only eight or nine years on average. This is due to dogs being a special case, as they were artificially bred by humans to select for looks or behavior and not necessarily health, and that considerable inbreeding was necessary to produce “purebred” dogs. For example, boxers are big dogs, but their higher cancer rates may result in a shorter lifespan. However, the really giant breeds all consistently live eight to nine years on average. So there is something going on besides simple breeding quirks that led to bad genetics and ill health. Something more general.

A few years ago, a large study [PDF] was published using mortality data from thousands of dogs across 74 breeds, testing three hypotheses: Large dogs may die younger than small dogs because of (1) an earlier onset of senescence, (2) a higher minimum mortality hazard, or (3) an increased rate of aging. The conclusion from their study is that aging starts more or less at the same age in small and large breeds, but large breeds age faster. We do not have a clear understanding of the underlying mechanism for faster aging in dogs. It seems that when we selected for large body size, we selected for faster aging as well. But we do not know all the genetic components of this. We know that there are at least three genes that determine large body size in dogs: IRS4 and IGSF1, involved in thyroid hormone pathways which affect growth, and ACSL4, involved in muscle growth, and back fat thickness.

But how this accelerates aging is still speculation. More studies are needed, but dogs seem to be a great model to study the evolution of body size and its relationship to aging.

This post originally appeared on Quora. Click here to view.

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Big Questions
Should You Keep Your Pets Indoors During the Solar Eclipse?
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By now, you probably know what you’ll be doing on August 21, when a total solar eclipse makes its way across the continental United States. You’ve had your safety glasses ready since January (and have confirmed that they’ll actually protect your retinas), you’ve picked out the perfect vantage point in your area for the best view, and you’ve memorized Nikon’s tips for how to take pictures of this rare celestial phenomenon. Still, it feels like you’re forgetting something … and it’s probably the thing that's been right under your nose, and sitting on your lap, the whole time: your pets.

Even if you’ve never witnessed a solar eclipse, you undoubtedly know that you’re never supposed to look directly at the sun during one. But what about your four-legged family members? Shouldn’t Fido be fitted with a pair of eclipse glasses before he heads out for his daily walk? Could Princess Kitty be in danger of having her peepers singed if she’s lounging on her favorite windowsill? While, like humans, looking directly at the sun during a solar eclipse does pose the potential of doing harm to a pet’s eyes, it’s unlikely that the thought would even occur to the little ball of fluff.

“It’s no different than any other day,” Angela Speck, co-chair of the AAS National Solar Eclipse Task Force, explained during a NASA briefing in June. “On a normal day, your pets don’t try to look at the sun and therefore don’t damage their eyes, so on this day they’re not going to do it either. It is not a concern, letting them outside. All that’s happened is we’ve blocked out the sun, it’s not more dangerous. So I think that people who have pets want to think about that. I’m not going to worry about my cat.”

Dr. Jessica Vogelsang, a veterinarian, author, and founder of pawcurious, echoed Speck’s statement, but allowed that there’s no such thing as being too cautious. “It’s hard for me to criticize such a well-meaning warning, because there’s really no harm in following the advice to keep pets inside during the eclipse,” Vogelsang told Snopes. “It’s better to be too cautious than not cautious enough. But in the interest of offering a realistic risk assessment, the likelihood of a pet ruining their eyes the same way a human would during an eclipse is much lower—not because the damage would be any less were they to stare at the sun, but because, from a behavior standpoint, dogs and cats just don’t have any interest in doing so. We tend to extrapolate a lot of things from people to pets that just doesn’t bear out, and this is one of them.

“I’ve seen lots of warnings from the astronomy community and the human medical community about the theoretical dangers of pets and eclipses, but I’m not sure if any of them really know animal behavior all that well," Vogelsang continued. "It’s not like there’s a big outcry from the wildlife community to go chase down coyotes and hawks and bears and give them goggles either. While we in the veterinary community absolutely appreciate people being concerned about their pets’ wellbeing, this is a non-issue for us.”

The bigger issue, according to several experts, would be with pets who are already sensitive to Mother Nature. "If you have the sort of pet that's normally sensitive to shifts in the weather, they might be disturbed by just the whole vibe because the temperature will drop and the sky will get dark,” Melanie Monteiro, a pet safety expert and author of The Safe-Dog Handbook: A Complete Guide to Protecting Your Pooch, Indoors and Out, told TODAY.

“If [your pets] have learned some association with it getting darker, they will show that behavior or at a minimum they get confused because the timeframe does not correspond,” Dr. Carlo Siracusa of Penn Vet Hospital told CBS Philly. “You might put the blinds down, but not exactly when the dark is coming but when it is still light.” 

While Monteiro again reasserts that, "Dogs and cats don't normally look up into the sun, so you don't need to get any special eye protection for your pets,” she says that it’s never a bad idea to take some extra precautions. So if you’re headed out to an eclipse viewing party, why not do your pets a favor and leave them at home. They won’t even know what they’re missing.

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