color vision / night vision notes

Noticed an article about color vision this morning: The Red and Green Specialists: Why Human Colour Vision Is so Odd. I’ve been thinking about the proliferation of blue lights in recent years. This article, and re-reading some of my bookmarks, helped me better understand why red and orange lights are especially useful for humans at night.

Long ago the lighting industry figured out that “Low Pressure Sodium” bulbs were pretty good for use at night. The orange light emitted by these bulbs is ideal for navigating the city at night, but not so good for color photography.

tl/dr: Human eyes’ most red-sensitive protein (red line, graph below) is highly sensitive to the orange light emitted by a low pressure sodium bulb. The second-most red-sensitive protein (green line, graph below) is less sensitive to orange light. Rhodopsin, the protein in rods that is responsible for low-light vision, is not (or barely) sensitive to orange low-pressure sodium light.

graph of response of human color vision pigments to different wavelengths of light
Normalised absorption spectra of the three human photopsins (solid curves) and of human rhodopsin (dashed curve). Orange bar placed at 590nm to denote location of LPS lamp spectrum. graphic: wikipedia / Photopsin

Rhodopsin rapidly degrades when it is exposed to light that it’s sensitive to. Rhodopsin is highly sensitive to green/cyan/blue light and slightly sensitive to yellow/orange light; low-light vision is most-attuned to green/cyan/blue light. Humans rapidly lose their low-light vision when exposed to higher levels of green/cyan/blue light. It takes about 30 minutes to fully recover enough rhodopsin to for us to see as well as we possibly can in low-light scenarios.

Protecting night adaptation

It takes about 30 minutes to fully adapt to low-light conditions. Ambient light (moonlight, skyglow) prevent most people’s eyes from fully adapting to low-light conditions. Because rhodopsin is not sensitive to red and orange light, using red/orange light preserves rhodopsin for a more-rapid recovery of low-light vision.

Cones vs. Rods

Cone cells have the various Photopsin photoreceptor proteins, and are responsible for color perception. Rod cells are photoreceptor cells in the retina of the eye that can function in less intense light than cone cells. Rods are more responsible for peripheral vision and low-light vision, and have more of the rhodopsin pigment.

Links and selected quotes

Sensitivity of Rod cells vs. cone cells

A rod cell is sensitive enough to respond to a single photon of light[11] and is about 100 times more sensitive to a single photon than cones. Since rods require less light to function than cones, they are the primary source of visual information at night (scotopic vision). Cone cells, on the other hand, require tens to hundreds of photons to become activated.

https://en.wikipedia.org/wiki/Rod_cell#Sensitivity

Understanding the change in human color vision sensitivity from photopic to mesopic and scotopic is essential for proper planning when designing lighting for roadways.

https://en.wikipedia.org/wiki/Sodium-vapor_lamp#High-pressure_sodium

Photopic vision is the vision of the eye under well-lit conditions (luminance level 10 to 108cd/m2). In humans and many other animals, photopic vision allows color perception, mediated by cone cells, and a significantly higher visual acuity and temporal resolution than available with scotopic vision.
Mesopic vision is a combination of photopic vision and scotopic vision in low but not quite dark lighting situations.[1] Mesopic light levels range from luminances of approximately 0.001 cd/m2 to 3 cd/m2. Most night-time outdoor and traffic lighting scenarios are in the mesopic range.[2]
Scotopic vision is the vision of the eye under low-light levels. The term comes from Greekskotos, meaning “darkness”, and -opia, meaning “a condition of sight”.[1] In the human eye, cone cells are nonfunctional in low visible light. Scotopic vision is produced exclusively through rod cells, which are most sensitive to wavelengths of around 498 nm (green–blue) and are insensitive to wavelengths longer than about 640 nm (reddish orange). This condition is called the Purkinje effect.

Sodium Vapor Lamps – Peak at 589nm and 589.56nm

Photopsin – “the photoreceptor proteins found in the cone cells of the retina that are the basis of color vision”.

Different opsins differ in a few amino acids and absorb light at different wavelengths as retinal-bound pigments.

Cone typeNameRangePeak wavelength[1][2]
S (OPN1SW) – “tritan”, “cyanolabe”β400–500 nm
(violet->Green)
420–440 nm
M (OPN1MW) – “deutan”, “chlorolabe”γ450–630 nm
(blue ->Red- Orange)
534–545 nm
L (OPN1LW) – “protan”, “erythrolabe”ρ500–700 nm
(Green -> Deep red)
564–580 nm

The loss of color perception in low light

The Purkinje effect (sometimes called the Purkinje shift) is the tendency for the peak luminance sensitivity of the eye to shift toward the blue end of the color spectrum at low illumination levels as part of dark adaptation.

Physiology

The Purkinje effect occurs at the transition between primary use of the photopic (cone-based) and scotopic (rod-based) systems, that is, in the mesopic state: as intensity dims, the rods take over, and before color disappears completely, it shifts towards the rods’ top sensitivity.[9]

The effect occurs because in mesopic conditions the outputs of cones in the retina, which are generally responsible for the perception of color in daylight, are pooled with outputs of rods which are more sensitive under those conditions and have peak sensitivity in blue-green wavelength of 507 nm.

Use of red lights

The insensitivity of rods to long-wavelength light has led to the use of red lights under certain special circumstances – for example, in the control rooms of submarines, in research laboratories, aircraft, or during naked-eye astronomy.[10]

Under conditions where it is desirable to have both the photopic and scotopic systems active, red lights provide a solution. Submarines are well lit to facilitate the vision of the crew members working there, but the control room must be lit differently to allow crew members to read instrument panels yet remain dark adjusted. By using red lights, or wearing red goggles, the cones can receive enough light to provide photopic vision (namely the high-acuity vision required for reading). The rods are not saturated by the bright red light because they are not sensitive to long-wavelength light, so the crew members remain dark adapted.[11] Similarly, airplane cockpits use red lights so pilots can read their instruments and maps while maintaining night vision to see outside the aircraft.

Rhodopsin (also known as visual purple) is a light-sensitive receptor protein involved in visual phototransduction. It is named after ancient Greek ῥόδον (rhódon) for rose, due to its pinkish color, and ὄψις (ópsis) for sight.[5] Rhodopsin is a biological pigment found in the rods of the retina and is a G-protein-coupled receptor (GPCR). It belongs to opsins. Rhodopsin is extremely sensitive to light, and thus enables vision in low-light conditions.[6] When rhodopsin is exposed to light, it immediately photobleaches. In humans, it is regenerated fully in about 30 minutes, after which rods are more sensitive.[7]

… Rhodopsin of the rods most strongly absorbs green-blue light and, therefore, appears reddish-purple, which is why it is also called “visual purple”.[12] It is responsible for monochromatic vision in the dark.[7]

An update for a neglected blog

About a year and a half ago my sister-in-law said something about how I should write something new for my blog, as the last post was (then) months old.

Lots of ideas for posts have crossed my mind, and while I’ve started a few, I never finished any of them. I have been researching and thinking, and working on my other websites and businesses, but teslabox.com has been neglected. Continue reading “An update for a neglected blog”

How Birth Control Torpedos Libido

[Update 10/8/2013 – at the bottom…]

My first post about birth control focused on cost — why the pharmaceutical industry’s contraceptive pills tend to be expensive. I’ve since realized that staying baby-free is much more important to women than the money spent on pills, no matter the cost. Given the choice between spending lots of money and likely becoming pregnant, women will spend the money, if they have it.

Every woman has a unique response to the pharmaceutical industry’s various birth control products. Some women can tolerate the $9/month generic. Others find they do better with the patent-protected pills that cost $100/month. Still others find that all “hormonal” birth control products are completely intolerable.

Birth control’s side effects are accepted as another cost to bear. The most ironic side effect is decreased libido. Many women find that the “hormones” they take so they can enjoy sex cause them to lose interest.

This is reflective of the industry’s chemical birth control products’ most fundamental problem: so-called “hormonal” birth control products don’t actually contain human hormones.

While the pills, implants and injections do a good job of suppressing ovulation and preventing pregnancy, all the side effects that women experience are caused by replacing Nature’s hormone with man-made chemical imposters. Continue reading “How Birth Control Torpedos Libido”

Why Birth Control Pills Are So Expensive

One aspect of the federally-mandated changes in insurance coverage of birth control products hasn’t gotten nearly the attention it deserves.

The problem that reformers were addressing is that birth control prescriptions are expensive. It’s not just the $60 or $100/month for a pack of pills. There’s also the $60 or $100 for an appointment with a doctor, and the followup visits for prescription refills.

If birth control was safe enough to sell over the counter for a penny or a dime a pill like generic aspirin, there would be no controversy. Religious figures could continue their teachings about birth control (and NOT be expected to pay for it), and women would make their own choices about actions they think are right for them.

Continue reading “Why Birth Control Pills Are So Expensive”

‘This Bill was BORROWED from Wall Street’

A one-dollar bill stamped with “I VOTED” recently spent a day or two in my pocket. I looked for a Where’s George inscription, but this was not present. This dollar, like all the others, wasn’t in my pocket for long before I traded it to a fellow human for something they’d produced with their labors.

For all the talk and theory, money is nothing more than a medium that helps humans value each other’s time.

Some months ago I wrote a letter to the editor about fixing the government’s finances, where I discussed how the money we trade with is created:

Under the present monetary system, money is created only when someone borrows it.

Usually, the federal government borrows a little money from the Federal Reserve, and the banking system expands this “seed money” 10 times (or more) by making loans.

Due to the failure of the banks to lend, the government has had to step in as “the borrower of last resort.”

Recently someone on a web forum thought Occupy Wall Street [OWS] protesters who advocate an audit of the Federal Reserve were stupid, because “The Fed is doing nothing illegal.”

My response was that we can’t really know whether the Federal Reserve Banks are operating legally without an audit, as the Federal Reserve system is rather secret about their operations. Furthermore, the limited audit that Senator Sanders got passed found that the U.S. central bank had some questionable behavior during the 2008 financial crisis, including the creation of an entire National Debt’s worth of money that was given to connected financial institutions – 16 trillion dollars, according to the Senator’s page.

The key point in my response were these lines:

If you have a dollar bill in your pocket, it’s only there because someone borrowed it from a banker. The bills are printed by the Treasury and purchased by the Federal Reserve at cost [4 cents?]. If you have a quarter or a dime or a Susan B. Anthony dollar in your pocket, the Fed bought these from the Mint for face value.

Sharing The Truth About Money

This is how I came to be thinking about the occupation of Wall Street, currency, and modifications to currency… How could the very core of the system for concentrating wealth and economic power be effectively conveyed?

I think a stamp would do it:

This Bill Was BORROWED From Wall Street:

Ideas are seldom truly original, so I searched on “occupy wallstreet currency stamp” (no quotes), and learned that people are just starting to put messages on currency. They’re calling it Occupy George. While the sentiment is right, their specific messages are entirely non-helpful.

Instead of focusing on the central defect of the modern banking system – that private banks create the economy’s money supply by making loans, starting with the seed money created by their 12 “Federal” Reserve Banks – they’re muddying the issue with meaningless messages about division of wealth that don’t lead to an obvious solution.

Yes, wealth is rather concentrated in the present day. But some people work for their millions, while others game the system. Increasing taxes on the people who’ve been especially successful will only perpetuate the L-Curve distribution of income because it does NOT address any of the curve’s CAUSES. Incomes are best balanced by creating a level playing field for all players in an economy, NOT by forcibly taking and giving.

A core element in motivational speaker Zig Ziglar’s philosphy was that “you can get everything in life that you want, as long as you help enough other people get what they want.” Instead of getting jealous that someone was in the right place at the right time, and worked to make the most of an opportunity, the present protests need to focus like a laser on individuals and groups that game the system.

Transitioning to a monetary system that uses money created by the national or state governments, as advocated by the American Monetary Institute and others, would do a lot to end the need for the present protests.

Currency Validation

I have a few dollars in my pocket, and a red pen. This Bill Was BORROWED From Wall Street. Ahh, much better. $5’s have much more blank space on the reverse than $1’s. 🙂 I think I will order a rubber stamp.

Perhaps the petitioners on Wall Street could set up a station for “currency validation”. Paper money is actually made of a blend of 25% linen and 75% cotton.  Currency validation pens change color if the bill is made of wood (paper), and the Secret Service has a helpful page for spotting counterfit currency. If the currency checks out, volunteers could stamp the bill as genuine: This Bill Was BORROWED From Wall Street.

Moving Beyond Protest

Fortunately, there’s no need to beg Congress to fix the laws to free us from the Federal Reserve’s yoke. I’ll be covering this strategy in my next post. Put your email in the box to the right if you’d like notification when this gets posted!

Job Projects for those who have nothing else to do

I spent a few minutes in a local supermarket yesterday, and noticed a man in the cafe who was making himself busy by pushing in chairs, and straightening tables and napkin holders.

He had a bit of a “homeless” look to him. A cart full of stuff confirmed my impression.

Everyone else in the cafe was sitting in a chair doing whatever they were doing – eating, drinking, checking email, etc.

I thought about telling this man that his constant laps around the room were making him stand out. If he’d just sit still and read his book for a bit, he could enjoy the air conditioning, and wouldn’t draw nearly as much attention to himself.

Today, outside the same store, I noticed this homeless man again near the bottle & can recycling center.  A few minutes later he was back ‘at work’, picking up trash and pushing in chairs.

It occurred to me that the worst part of being unemployed, homeless and living on the street would definitely be the boredom.

One of the problems with the market economy is that a certain percentage of the population is basically unemployable, for a variety of reasons. Mental illness, health problems top the list, and others just never learned a skill that’s marketable.

Make-work projects are those from which little value is created. The classic example of a make-work job program is paying one person to dig a ditch, and paying a second person to fill it in.

To me, a ‘job project’ is something that puts people to work doing things that ought to be done anyway. There are always weeds that need to be pulled, public structures that need a fresh coat of paint, graffiti vandalism painted over, etc.  I imagine a program where the crew chief would take whoever shows up and put them to work doing whatever needs to be done.

There could be big jobs projects too. The maintenance and building of bridges and other forms of infrastructure is one possibility. The American Society of Civil Engineers grades the United State’s infrastructure at a D- (just above failing).

On the other hand, direct government employment may be the only solution to some of our most serious long-term unemployment problems: structural unemployment.

… People who cannot find jobs because they lack relevant skills of any kind best fit the definition of “structural unemployment.” It seems pretty clear that neither policies that change job search behavior nor policies that expand spending in general are very suited to this group.

http://web.archive.org/web/20090423213059/http://william-king.www.drexel.edu/top/prin/txt/controv2/un12.html (emphasis added)

Paying for it all…

Many people’s first objection is probably about the cost: “Who’s going to pay for this?”,

As I alluded to in my recent letter to the editor, the government’s most important job is managing the money supply.

While there is a case to be made that the government can’t be trusted with something this important, practical experience shows that private banks have failed to facilitate an equitable distribution of money in the economy.

If the government were to create more of the money supply, this could be spent directly into circulation. Right now, the only fraction of the money supply that it creates are coins, which are purchased by the federal reserve at face value and distributed to the banking system.

Imagine having the money to do a task properly…

A few months back I saw a crew of two men spraying something into the blackberry bushes that grow between the creek and the trail. I said that I’d just moved to Oregon, and asked what they were spraying for. I learned that  Blackberries are considered noxious weeds in Oregon, and that the city has to spray to keep the vines from completely overgrowing the trail.

After two weeks there was a band of defoliated blackberry vines about 3 feet thick. 20 feet of blackberries with green leaves were behind this band.

Instead of having the city pay to spray a large amount of herbicide on these bushes, why not have work crews completely clear blackberries out of the entire 20-mile trail? This is much more expensive than two guys with a herbicide sprayer, but the job would be done right.

The war against blackberries can probably never be won, but at least this section of trail would be blackberry free for a while.

Perhaps blackberry trimming isn’t the greatest example of what could be done but for lack of funds.

Many existing jobs are actually make-work

The number of people incarcerated for victimless crimes has exploded in recent decades. While it’s important to be able to segregate problematic members of a society, a large percentage of the prison population are more political prisoners than genuine potential hazards. The largest portion of these “political prisoners” were put there by the so-called “war on drugs”.

Prison is extraordinarily expensive, much more so than any job project I can think of. The cost of a jail bed averages out to about $62/night. Eight hours of work at $7.25/hour (current minimum wage) is $58.

Much more value is created by putting someone to work than locking them up.

Rather than locking someone up for petty offenses (of which many are economically driven), society would turn a lose-lose situation into a win-win.

Education is another example of a sort of make-work program. While education itself is very important, the government currently spends $billions more educating children than it needs to.

Young people are currently subjected to entirely too much schooling. Accelerated learning methods allow just about anyone to make exponentially more years of progress in a single year than in the present system. See my recent post about the fellow who was trying to get a young man to care about school.

Putting people to work

An estimated 14-million people are currently unemployed, and millions more are working less than they’d like. The government needs to step to the plate, and provide  money to put people to work.

Some final thoughts from someone with more certifications in Economics than I:

… Nothing could be more foolish right now than policies that reduce government spending or increase taxes. We have nearly 14 million unemployed people in the United States, a number that undoubtedly underestimates the true magnitude of the problem since it ignores discouraged workers and the underemployed. Despite this, Messrs. Obama, Ryan, and Geithner tell us that we need to make sacrifices. Seriously? The American people already have, and what they are asking us to do will simply make it worse. 

Why You Should Learn to Love the Deficit: Federal Budget Fallacies

Fixing the Government’s Finances

I used to write a lot of letters-to-the-editor. It was mostly an exercise in futility – it’s been about 8 years since I sent the first one, and still nothing changes.

The constant talk from the mainstream media about the “debt ceiling” is rather irritating, and this letter sorta flowed out of my fingertips. The Arizona Republic saved it most of a week to put in their Sunday paper.

One of my signatures for message boards is “learn the rules so that you know how to break them properly”. This means that we must understand the systems that we interact with to maximize our personal freedom.

The present debt ceiling uproar is a completely contrived crisis. Most of the members of congress are completely clueless about what they’re arguing about.

This was my effort to help people “learn the rules” about finances:

GOP, Dems don’t understand banking

Can we please get past all the hot air about the government’s finances?

Everyone is talking as if the logic applied to household and corporate finances applies to the government.

The formula for household fiscal solvency is “spend less money than you make.”

The government gets different rules because it’s the one that’s supposed to make the money that households spend.

(continued inside) Continue reading “Fixing the Government’s Finances”

The opposite of genius

Haven’t posted anything in almost a year. I get a lot of inspiration for blog posts, but haven’t actually taken the time to flesh many of them out. Sorry about that. 🙂

I was at a local cafe this morning with my laptop. A 60-something year old man sat down at a nearby table with a pair of teenagers – a 15 or 16 young man, and a 2-3 year older young woman. The young man had red hair. I couldn’t help but overhear the lecture.

It wasn’t a stern lecture – the gentleman just wanted to share some helpful advice about doing well at school. Take notes, review notes, ask questions.

This is a great strategy, if you care about the subject. But it’s exceedingly difficult to care too much in a standardized school environment. Even if the ‘kid’ tried to implement the advice, I’d be stunned if the effort continued past the first week of school.

That’s how it always was for me, anyways: “this year I’ll have good habits”, but it’d never last. I spent 16.5 years getting formally educated. Most of that time was spent coasting, doing the bare minimum for most of the classes I took…

Anyone can learn just about anything, if they care about the topic. There’s a quote about how it only takes is an hour of concentrated study a day to become an expert on just about any topic in a year.

If I’d been the one offering a possibly troubled young man advice, I would have started by asking what he’s interested in. What’s exciting, what does he look forward to?

At least that way the money spent on coffee wouldn’t be wasted.

When Disaster Strikes, Send The Enterprise

Whenever a disaster happens here on Planet Earth, the first responders frequently come from the Military/National Guard. They have manpower, equipment, and financial resources to respond to the unexpected.

Today humanity’s greatest challenge is dealing with Mother Earth’s curveballs… Floods, Tsunamis, and Earthquakes can all dramatically upend the lives of affected people, anywhere on the planet.

Rather than throwing together a response to the disaster-du-jour (of the day), we should have ships on standby that are prepared and ready to lend assistance to the people who need it.

www.SendTheEnterprise.org.

Continue reading “When Disaster Strikes, Send The Enterprise”

Cleaning Up the Gulf of Mexico

In June I formulated a plan to help clean BP’s oil from the Gulf of Mexico. To Save the Gulf, Send The Enterprise calls for using the U.S. Navy’s portable nuclear reactors to power air pumps for oxygenating ocean waters in the Gulf. Bacteria already present in the ocean use oxygen to consume whatever oil they encounter.

A lot of people really liked the idea. One commenter suggested that instead of blowing bubbles into the depths of the ocean, warm surface water could be oxygenated and pumped instead. Pumping air below a couple hundred feet would have required much more energy than pumping water.

When the oil volcano was gushing, the bubblers would have been concentrated in rings around the wellhead. BP’s well has now been capped, but there are still plumes of oil that need attention.

Mother nature will slowly take care of this task, but it will happen faster if the Navy is put on task. The fleet’s submarines are each powered by a portable nuclear reactor, and the Navy certainly has a few spare reactors sitting around.

Once most of the oil has been consumed, the pumps can be used to treat the ‘dead zone’ that appears at the mouth of the Mississippi river every summer:

Summer rains wash nutrients, dissolved organic matter and sediment out of the mouths of rivers, into the sea, sparking large phytoplankton blooms. …

Enhanced phytoplankton blooms can create dead zones. Dead zones are areas of water so devoid of oxygen that sea life cannot live there. If phytoplankton productivity is enhanced by fertilizers or other nutrients, more organic matter is produced at the surface of the ocean. The organic matter sinks to the bottom, where bacteria break it down and release carbon dioxide. Bacteria thrive off excessive organic matter and absorb oxygen, the same oxygen that fish, crabs and other sea creatures rely on for life.

Mississippi Dead Zone (emphasis added)

So what if it’s expensive? Wealth is created when people work to solve problems, doing research, building supplies and equipment. Wealth is squandered when people sit around unemployed.

This proposal is by no means complete, and a lot of research still needs to be done on how to best clean up the gulf. But we can start building and deploying compressors and pumps to treat the water today. Scientists and engineers will figure out the best ways use the equipment.

This project is more than a cleanup – it’s an investment in our future.