At What Point is a Human Considered Officially Dead?


Zoe-Anne Barcellos:

Legally, you are not dead until someone says you are dead.

You can be pronounced or declared dead. Each state in the USA has its own statutes that cover this. Typically a doctor or nurse can pronounce, and everyone else (police officers, EMTs, firefighters) will declare death.

One of the hardest parts of my job is estimating the PMI, or the Post Mortem Interval. This is the amount of time that has elapsed since a person's biological processes have stopped and they were pronounced dead.

We use several methods to determine this—rigor mortis, algor mortis, palor mortis, stage of decomposition, insect activity, etc. But they are all an educated guess, and most coroners or medicolegal death investigators will tell you “sometime between the last credible witness of when they were alive and when they were pronounced.”

But any estimate given is in a time span of several hours to days. It is not like TV and movies where they narrow it down to minutes.

But the time listed on your death certificate is the time you were pronounced. If you were in the hospital, this most likely will be at, or very close to, the time your biological processes stopped, i.e. your heart stopped beating or breathing stopped. It could also be when you are declared “brain dead.” Brain death requires several specific tests, and it usually has to be done by more than one physician.

If you are not in the hospital at the time of your death, then it will be when someone finds you.

This can cause some legal issues with regard to inheritance, but that is usually determined in court. The death certificate will not be amended, as your time of death is when you are pronounced.

For example, neighbors report to police the sound of a gunshot. Police go and find Joe Brown with a SIGSW (self-inflicted gun shot wound), he is still warm and it is obvious that this just occurred. Medics come in and declare the death at 07:30 hours. Police are investigating the scene and several hours later find his wife decomposing in the basement (or solidly frozen in a freezer). Police don’t even call in medics, they declare her at that time. The wife’s time of death will be on the same date at 10:45. Obviously she has been dead much longer, but the time of death on the death certificate is when she was found.

Now let us assume they are wealthy, and both have children from earlier marriages. Then you can have a whole legal battle on your hands!

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

What Are the Santa Ana Winds?

Satellite image of Santa Ana winds in Southern California.
Satellite image of Santa Ana winds in Southern California.
NASA/JPL-Caltech, Wikimedia Commons // Public Domain

Two massive wildfires burning in California have now become the state's deadliest and most destructive. In Northern California, the Camp Fire near Chico decimated the town of Paradise and killed 29 people as of November 12, 2018. In Southern California, the Woolsey Fire started near Simi Valley northwest of Los Angeles, and has torched hundreds of homes in Malibu and other communities.

The National Weather Service says that a combination of high temperatures, low humidity, and gusty Santa Ana winds have created perfect conditions for cataclysmic fires.

What are these Santa Ana winds and why do they help create fire conditions?

Santa Anas are dry, warm (often hot) winds that blow westward through Southern California toward the coast. They're usually seasonal, and typically occur between October and March and peak in December. They originate when high pressure systems form over the high-elevation deserts of the Great Basin between the Sierra Nevadas and the Rocky Mountains. Air from the system flows clockwise, so winds on the southern side of the system push west towards the Pacific Ocean.

The winds pass over the mountains between coastal California and the inland deserts. As they flow downslope, the air gets compressed and rises in temperature at a rate of almost 29 degrees per mile of descent. While air's temperature rises, its relative humidity drops, commonly to less than 20 percent and sometimes to even less than 10 percent. The winds also increase dramatically in speed when they're forced through narrow mountain passes and canyons.

By the time the winds hit the coastal areas, they're very dry, warm, and moving fast. This is what makes them problematic. They dry out vegetation, making it better fuel for a fire—and once a fire starts, the winds fan the flames and help spread them.


So, why are the winds called "Santa Ana winds"?

"While the origin and cause of the Santa Ana winds are not in dispute," writes Robert Fovell, currently a professor of atmospheric and environmental sciences at SUNY Albany, "the origin of the name is."

One fairly popular explanation is that the name comes from a Native American word, santana, which means "devil wind" and was corrupted into Santa Ana. But according to Fovell, the Los Angeles Times, and other sources, no one has found any words similar to santana with that definition in any of the native languages of the area.

Another explanation is that the winds were named for Mexican politician and general Antonio López de Santa Anna, possibly in reference to dust storms kicked up by the cavalry he commanded. Santa Anna never operated in southern California, though, and spelled his name with two n's. The Oxford English Dictionary dismisses this etymology as having no foundation.

In the early 1930s, an article in the United States Naval Institute Proceedings suggested that the name might have originated with early Spanish explorers, who had a "custom of naming places and events for the saint's day on which they happened or were discovered." In this case, they might have noted the winds on St. Anne's day and named them for her. This also seems unlikely to historians, though, because a few Santa Ana winds, experienced for the first time, probably wouldn't have warranted naming—and the winds aren't recorded with any name until much later, anyway. St. Anne's feast day is also July 26, when a Santa Ana wind is unlikely.

The most common and accepted etymology, says Fovell, is that the winds' name simply derives from the Santa Ana canyon in Orange County.

This article was originally published in 2014 and has been updated.

Why Do Babies Learn to Crawl Before They Walk?


Fabian van den Berg:

Babies walk or dance before they crawl actually, well sort of, you’ll see.

Babies are amazing little creatures. They are very different from adults and should be treated as such. They aren’t born as blank slates, though; a lot of things are innate, and a lot of things are learned. And boy can they learn—not just by watching others do things, but also by experimenting. There’s a reason why early developmental psychologists called them "little scientists." They will form strategies on their own, test them out, and choose the best one.

We’ll focus on walking for now.

Newborns come fully equipped with a stepping reflex. If you happen to have a newborn at your disposal you can try it out (but support the head). By dragging them a bit over a surface, the feeling of their feet/soles touching will initiate a stepping reflex, it looks like they’re walking. (Don’t let go though, they are definitely not ready to stand on their own yet and will fall down.)

The reflex tends to be present for the first two months, sometimes returning right before they start to walk. It’s thought that the reflex helps to train the muscles and motor nerves. The reason why it disappears is thought to be because the legs become too heavy, the muscles grow faster than their strength. Basically, they become too chubby and the reflex doesn’t work anymore.

In a way, they are born with the ability to walk or dance (it differs a bit from baby to baby), but then lose it again because they grow so fast.

There are a lot more interesting and fun baby reflexes, like swimming and grasping, but that’s for another answer.

That brings us to toddlers and locomotion: Many parents will attest they looked forward to their baby being able to move on their own, and as soon as they did they missed the times the little bugger would stay put.

Infants can be very motivated, which is where the little scientist pops up. Having toys or anything interesting looking sitting around is very tempting. Kids love touching things, they explore, and they really want to go there… But how…

Should they wait for the big person to either bring them there or bring the shiny to them? No, of course not. They can move now—so off they go!

They will experiment and explore a lot of different ways of getting around. A very popular one is scooting. They are laying there (they’re good at that), but they want to be elsewhere. Almost all children will solve this conundrum by pulling or pushing themselves using their hands [and] scooting or shuffling across the floor. A popular and funny variation is scooting on their bums. If they can sit, they’ll prefer to sit and just use their arms and legs to push themselves around.

It’s not uncommon for children to be in this stage until they learn how to walk. It really is a matter of what works best for them.

Crawling is merely a more advanced version of scooting. Their legs become stronger and they are able to control them better. They will happen upon crawling by trial and error, and find that it can bring them from Point A to Point B faster than scooting.

The logic is simple to follow: I want to go over there, crawling works best, so crawling it is.

Strategy use is very common in children, you see it in many aspects. They will try out new things, compare it to old things, and decide on whatever works best. In the case of crawling it’s mostly about speed. But as I said before, not all kids crawl. For some scooting works best, and they’ll use it until they learn how to walk.

It’s also not strange to see them use different strategies, sometimes crawling, sometimes scooting. Usually this occurs when they are learning and experimenting with new strategies.

Children don’t need examples to learn, they are very capable on their own. They will try and discover things like the small scientists they are.

Crawling is one of those things. They don’t need to see it, they discover it, realize it works better than what they had before, and start using it more and more until something better (like walking) comes along.

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