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Comment Re:Wireless charging? NOT POSSIBLE. Breaks Phys la (Score 1) 136

Oops. You are right and I knew that, with a part of my brain that obviously went unused. But yes, already damning case even worse.

If they want to do something constructive, they could make their damn phones waterproof to 2m by default and make it use an inductive charger by default. Building a phone that not only dies if you get a single drop of water NEAR the charging port but then clicks over to void your warranty was evil from the beginning.

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Comment Re:Wireless charging? NOT POSSIBLE. Breaks Phys la (Score 5, Informative) 136

t's really weird how people who know NOTHING about PHYSICS assume they can make decisions about technology.

I teach physics. In fact, I teach electrodynamics, off and on. Is it possible to charge a cell phone with wireless technology? Sure. All you need is a big enough tesla coil and a big enough loop and the ability to rectify broadband noise. If you are radiating a couple of hundred watts you can probably pull a watt out of it if you aren't too far away. Of course, you can also cook a hot dog if it isn't too far away.

Now let's consider 802.11 signals. The signal strength is limited to 1 watt by the FCC, but IEEE specs peg it at 23 to 24 dBm (200-250 mW). One whole watt is 30 dBm in decibels(milliwatt), and you can get an effective gain of 6 dBm (x4) or 4 watts with the antenna:

https://www.air802.com/fcc-rul...

Most wireless receivers operate with signal power (coming into the receiver antenna) in the ballpark of -10 dBm to -100 dBm, where at the low end of that range one is likely down in the noise. That is (translating to power) 100 microwatts down to 10^{-13} watts (10^{-10} milliwatts). If one takes the average cell phone's surface area -- maybe 50 or 60 cm^2 -- and compare it to the radiating solid angle of a transmitter just 50 cm away, it is a very small fraction -- order of 50 to 50^2 or order of 1%. So if one starts with 200 mW and receive it with 100% efficiency around a half meter away, one would be lucky to get more than around 1 mW. USB cell phone wall chargers, OTOH, typically use 1 to 2 W, and still take hours to charge a discharged phone. We could anticipate charging times of order 1000 hours, then, at a mW trickle.

The one place and way this MIGHT work, then, is if one places the phone ON the 802.11 transmitter, just outside of the antenna, close enough that the phone subtends at least 1/10 of its radiation pattern. Assuming a 36 dBm antenna signal strength (4 W), picking up 0.4W, with maybe 0.1 to 0.2 W usable power input after accounting for RMS power and efficiencies, you would be to the point where one might be able to recharge a partially discharged phone in a day.

The big question is then, who would want to do this? A normal 23 dBm transmitter would take weeks to charge the phone even sitting on top of it, and the phone itself would be sucking up the signal you need for your devices to operate. It would still take all day to charge instead of a few hours. It would (probably) cost more than existing "charging pads" that do the same thing and charge your phone wirelessly through induction and an inverter. It would interfere with your 802.11 device and likely reduce its effectiveness at the purpose for which it was intended. It's like "hey, we can build an antenna so that if we put your phone in the microwave oven, it will recharge it really quickly, if we shield the phone and don't mind possibly ruining the microwave". Sure, but why would we, when wall-warts and a cable cost $15, when solar chargers that actually work and don't leach power from 802.11 devices cost less than $100, etc?

The one thing you will NOT be able to do is to recharge your phone from across the room, or keep your phone charged by just sitting in the same room as an 802.11 transmitter. You'd need a phased array of antennae a half-meter wide to get enough directional concentration across a room, and it would make your transmitter pretty much useless as an actual transmitter for 802.11 devices long before that. Even if you pulled ALL the power from a 23 dBm transmitter the numbers just don't make sense for this.

Comment Re:Gut flora and artificial sweeteners (Score 1) 5

This is probably the most recent, well-cited article on the topic. The authors looked at the effects of saccharin in mice, and were able to determine that there was a significant elevation in blood-glucose level for the mice that were fed saccharin instead of actual glucose over the course of nine weeks. This suggests a mechanism for previous findings that suggest artificial sweeteners cause insulin insensitivity, weight gain, type II diabetes, et cetera. The difference between the two diets went away when both groups were raised with antibiotics, strongly suggesting the underlying cause was gut microbiota. They also found evidence that the saccharin diet led to changes in gut microbiome composition:

In agreement with the experiments with antibiotics, next generation sequencing of the microbiome indicated that mice drinking saccharin had distinct compositions from controls. This distinct microbiome was characterized by enrichment of taxa belonging to the Bacteroides genus or the Clostridiales order, with under-representation of Lactobacilli and other members of the Clostridiales. Several of the bacterial taxa that changed following saccharin consumption were previously associated with type 2 diabetes in humans.

Keep in mind that everyone has different gut flora, so in general these impacts will vary from person to person, which is why the effect is inconsistent, as with obesity and type II diabetes in general. I can't say for certain that these results would directly transfer into humans, but since the bacteria are the same, it's unreasonable to assume they wouldn't. Less clear is whether this effect transfers to other sweeteners; the paper includes a table showing a number of studies pertaining to a diversity of chemicals, some of which found an effect, and some of which didn't.

Non-professionally, my advice would be to avoid artificial sweeteners, and ideally all liquid candy. Some people find that drinking normal, sugary soda produces a state of lethargy, and I'm pretty sure this is a result of the long-term exposure to sucralose. It's sort of a trap!

Comment Re:Which type of graft is best? (Score 1) 5

That's fairly straightforward; as this summary article explains, a synthetic allograph (or xenograph; the terms overlap) that maintains bone mineral density is ideal, as it means no harvesting from elsewhere on your body (eek), no risk of rejection, and good bone density. I'd say start a conversation with your dentist about hydrogel-hydroxyapatite composites and mention you're concerned about sustaining bone density long-term.

Comment Re:Question for the Physicists. (Score 3, Interesting) 79

Here is a really cool fact that you can use to impress chicks at cocktail parties: A magnetic force and an electrical force are the SAME THING. The only difference is your inertial frame of reference. Let's say you have two parallel copper wires with current flowing through them. The negative charge in the electrons and the positive charge in the copper nuclei should cancel each other out, and there should be no force between them. BUT THERE IS. This is magnetism. But it is really just plain only electrical attraction because the electrons are moving, so their inertial reference frame is different from the reference frame of the copper nuclei. A moving reference frame has a Lorentz contraction, so the copper nuclei "see" more electrons per length of wire, resulting in an attraction.

No. Magnetic and electrical force and energy aren't exactly "the same thing". The magnetic and electric field are both components of the second rank field strength tensor, the Lorentz force in electromagnetic theory is not just the Lorentz transform of the Coulomb force, and magnetic and electric field energies are independently summed when assembling the total electromagnetic field energy density. Finally, good luck describing electron spin and the resultant intrinsic magnetic dipole moment in terms of a Lorentz transformation of the bare Coulomb field of the (point) charge -- there is no rotating frame or mass moving around mass.

There are basically two different ways to discuss them. One way is to stop talking about electric and magnetic fields independently at all and only work with the electromagnetic field (strength tensor) where the electric and magnetic components are NOT THE SAME and do NOT HAVE THE SAME SYMMETRY. The other way is to pretend (as most intro books do, because usually it works pretty well if you're considering low velocities and coarse-grain-averaged "smooth" charge/current densities) that E and B are ordinary vectors and write down Maxwell's equations. There are FOUR of them -- two if you go with the covariant field strength tensor formulation, and you cannot write them all down in terms of a single vector field (or the resultant force).

F_e = qE (F, E vectors)
F_b = q v x B (F, v, B vectors)

The electrostatic force obeys Newton's third law. The magnetic force (with the cross product) does not,. and one has to work very hard indeed to find the missing energy and momentum in the electromagnetic field when two charged particles interact in the general case.

Sadly, I haven't found that knowing graduate level electrodynamics well enough to teach it impresses chicks at cocktail parties.

User Journal

Journal Journal: Biology Help Desk: Volume 3^3 5

As requested by the world's greatest masked mystery person, Anonymous Coward, it may or may not be time for yet another biology help desk thread, after a surprisingly long hiatus of about four years. Feel free to contribute both questions and answers.

Comment Re: In Other News (Score 1) 478

It was a quaint archaism over a century ago. British English used it in the 18th century, and it arrived in India alongside the British. Many quirks of Indian English have similarly ancient roots, although some are innovations and most are the product of people learning the language (e.g. Hindi speakers conflate "softly" and "slowly" as Sanskrit had only one word for both.)

Comment And the amazing consequences... (Score 5, Funny) 606

Two words: Wikipedia vandalism.

According to Wikipedia, the Whopper is a bugger consisting of a flame-grilled patty made with 100% medium-sized child with no preservatives or fillers, topped with sliced tomatoes, onions, lettuce, cyanide, pickles, ketchup, and mayonnaise, served on a sesame seed bun.

Comment Re: oh no (Score 5, Funny) 423

All. Almost all. Slashdot is the unpleasant-smelling uncle at the Thanksgiving dinner table who was laid off during the dot-com bubble, decided to retire early, and spends the rest of his days complaining about how new-fangled touch-screen smartphones don't support vi keybindings the way God and Ken Thompson intended, how systemd would never have happened under a Libertarian president, and that global warming is a feminist conspiracy.

The rest of us come here because it's mildly more entertaining than going to an actual zoo.

Comment Re: "visible in small optical telescopes" (Score 1) 44

Seriously? When I see Jupiter (which is coming up right around dark, the brightest thing in the sky to the west besides this week's full moon) it doesn't seem that scary. Why do you cringe? Venus is quite beautiful as well. With my 10" scope I can take Saturn -- easily seen with the naked eye -- and magnify it to where we can see its rings and moons. As for meteors, I remember lying out on a dry lake bed far from city lights during one of the better meteor showers -- can't recall any more which one -- and seeing an absolute rain of them, two or three per second, for hours. Quite the opposite of a cringe-worthy experience.

You must be a very delicate soul, if tiny lights in the sky make you cringe, or if other people talking about seeing the tiny lights makes you cringe.

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Comment Re:Positive (Score 3, Interesting) 316

People who lived paycheck to paycheck had NO health insurance. This was the problem obamacare was trying to fix. Something like 20% of the population of the United States has no insurance or terrible insurance. You can try to pretend that this isn't true, you can assert loudly that it is "their choice" not to buy insurance, but -- remember, they are living PAYCHECK TO PAYCHECK or on NO PAYCHECK AT ALL. If they chop out $200 to $300 each month (or far, far more) for insurance, you're just saying that they have a choice between eating, or wearing shoes, or living somewhere other than under a highway overpass, and health insurance.

My wife is a physician and has been taking care of these patients for her whole career. Your "free market" solution for most of her career was this: If an indigent patient (or one who lived paycheck to paycheck, or one who just couldn't/wouldn't afford to pay) walked in to see her, she could see the patient, accept whatever medicare (elderly) or medicaid) (poor) payments they might qualify for -- well under the market value of her billable time -- or just see them pro bono, which she might well do for a patient she'd been seeing who lost their job. Hospitals were in an even worse state. If somebody walked in off the street into a hospital ER, they were LEGALLY OBLIGATED to take care of them, whether or not they could pay. Even a very small hospital/ER visit costs a lot of money, and medicare/medicaid (if it pays or paid anything at all) payed only a small fraction of the actual cost of the visit.

Your "free market" pre-obamacare solution was thus to screw the physicians and hospitals and nurses by simultaneously requiring them to provide medical treatment to people who couldn't afford it and exploiting their good nature on top of that for people living on the edge of the poverty who -- at best -- could only afford to pay something much less than the cost of the service and cannot possibly afford even the cheapest health insurance. And before you even start, let me assure you that for a physician in pretty much any practice, overhead is AT LEAST 2/3 of their billing, maybe a little bit more, so a free patient isn't just a matter of a physician contributing a bit of time, it is contributing their own time and PAYING their nurses, receptionists, PAs, for the lab (and any labs they order) and of course there is the building itself and all utilities all paid OUT OF POCKET -- directly eating into their income. This isn't a zero sum break even games, they lose money for underbilling and collectable accounts, and medicare/medicaid doesn't even pay for the overhead on the visits they supposedly pay for. So yeah, in order not to go broke WHILE working 60-65 hour weeks for half of what they would be making in a "free" market, they charge 30% more to everybody else (more like 100% in hospitals, where hospital ERs are the most expensive possible way to deliver routine health care). Guess what! You've socialized medicine, but in the worst possible way, the least fair way. And the saddest thing of all is that people don't even realize that this has happened, and yammer on about free markets and how having competitive insurance plans is somehow optimal and can take care of everybody that needs -- is mandated in law -- to be taken care of.

Obamacare didn't fix this problem, of course. It did, however, make it a lot better, and more fair, in that by increasing the number of the insured and directly subsidizing insurance for the working poor who previously had to rely on the charity of doctors or hospitals to get medical treatment or routine well-patient care, they passed the costs on to the people of the US collectively instead of forcing the physicians and hospitals individually to do what they insisted that they do, at a loss. And I'm not just talking the unemployed, I'm largely talking about precisely those living paycheck to paycheck, often working several jobs because employers don't want to have to provide benefits and only let them work 30 hours a week (each). I have three sons doing just this, and without obamacare and the 26 year old rule only one of them qualifies for an employer group health plan, and THAT is so expensive that he opted for high deductible insurance (so they could afford food, clothing, day care) and got totally screwed when he had a major health issue that lasted two years before they finally figured it all out. One is on obamacare, and as the person who actually pays for the insurance I can assure you that it is way cheaper than it would be otherwise. One is still on my group health insurance (for five more years, if congress doesn't trash a perfectly good thing that yes, I'm paying for but at group rates).

My wife is firmly convinced that unless and until we go to a single payer system, health care in the US will remain the way it is now: massively broken. We are all firmly convinced that if the US congress were required by law to use the health coverage they think is "adequate" for medicaid or medicare patients or if they were required by law to get their health care through the national VA hospital system (my wife currently works for the VA and has to wrestle with that special brand of crazy that dominates it) all of this would literally be fixed overnight. The US is behind almost all of the developed world in the tortured and demented way we provide insurance and drugs and health care. The system is anything but a free market, and as long as human poverty and disability and greed remain the way that they are will never BE a free market unless you are prepared to see people literally dying on the streets for a lack of health care.

Most people think that would be a bit barbaric. I certainly do. Beyond that, the only question has always been: Do we come up with a plan that is universal and fair, or do we try to force physicians to cover the vast distance between universal and fair by hiding the costs of universal under a thin veneer of "capitalist" respectability that makes it both socialist anyway and incredibly unfair. While (double bonus) maximizing the profitability of the insurance and big pharm industries and maintaining those all-important political contributions to BOTH parties from the insurance and big pharm megacorps.

Human rights are, of course, an illusion; life in a state of nature is ugly, nasty, brutish and short (to semiquote Hobbes). We INVENT things like the right to life, liberty and pursuit of happiness and it is up to us to invent and establish a society where those "rights" have some meaning. It is up to us and only us to determine whether the right to "liberty" means "the freedom to starve" in a world where we have sufficient wealth to provide a decent living for every single human and still have plenty of room left over for a strong system of differential rewards for labor and sacrifice. This "utility pool" is only going to become broader and deeper over time as we invent ever more labor saving devices -- robots, automated manufacturing, sales, and delivery systems, tractors that run themselves, cars and trucks that drive themselves. We can do a lot better than the freedom to starve, the freedom to suffer and sicken and die, a life where happiness is literally impossible to pursue due to the accidents of our birth, the accidents of our life, or the vagaries of the economy.

Was obamacare a perfect solution? Of course not. With the entire country polarized, ripped apart between competing and utterly illusory memes of the ideal free market capitalist society and the ideal managed market communist/socialist society, mere common sense didn't stand a chance, and still doesn't. Congress votes on the basis of a complex religion that doesn't even have a fixed scripture or universal set of rules, and congress is for sale because we have systematically created a democracy where one cannot even dream of running for office without a stupendous budget for advertising, a budget that can only be realized with corporate money, money that only appears in your coffers if you promote policies that don't bite the hands that fill the coffers and from time to time throw them a juicy pork bone. With Big Pharm and all the insurance companies and HMOs in the country advocating on both sides of the aisle for solutions that let them continue to make enormous profits, how could anything work? And hospitals and doctors themselves aren't always saints either, but forcing them to do what we wouldn't force a mechanic to do -- to fix EVERYBODY's car, and if you can't afford to pay for it, well, the mechanic is responsible for buying the replacement parts and fixing it and paying all the overhead for his tools and garage and don't forget taxes on all of the above -- is not a reasonable or fair solution.

And before you go there, things that would work for cars (which we can at least imagine are NOT actual necessities of life itself, so sure, forcing people to earn the money to support them or do without is at the very least less crazy) would not work for people, at least not unless you are comfortable passing the corpses of men, women and children abandoned on the side of the road the way we now sometimes see dead cars.

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