John Salerno

Anyone?

I've been trying to dispel the myth (in my family) that being out in the cold causes you to catch a cold. Naturally I try the simplest approach and say that a cold is caused by a virus, and unless you actually catch a virus while out in the cold weather, the actual cold itself won't make you sick. Likewise, it is believed that standing under a ceiling fan with your head wet can make you sick. Or going outside with your head wet causes pneumonia, etc. As far as I know and have read, none of this is true. The closest I've come to anything suggesting otherwise is that maybe some viruses are more prevalent during the cold months, which makes them easier to catch. But again, it doesn't really mean the *cold* itself is causing an illness.

Although the thing about a wet head and pneumonia seems even more deep-seated. Is there any truth to that one?

And now to my topic: another thing I can't quite seem to dispel is that if the wind is strong enough and it blows in your ears, you can get an ear infection. Again, I just don't see how this is medically possible. What *does* seem possible is perhaps with enough pressure from the wind, you can get an earache, but that is distinct from an infection (which again must be viral or bacterial, and not just a "wind infection") and most likely temporary.

So is there any truth to the wind causing problems with your ears? Do the answers change for children vs. adults?

Thanks.

Try this.

 

You need to work out your last common ancestors, which are your Great-grandparents (their grandparents). Thus you are 1st cousins once removed.

Yes, Wikipedia is where I was reading, but I guess I didn't go back far enough when figuring out our last common ancestor. But according to the definition of degree, someone "with whom you share a great-grandparent (but not a grandparent or a parent) is a second cousin," so that seems to imply that my relative in question would be my second cousin.

And they are "once removed" because they are first cousins of my parents, which means they are a generation away from me? Is that the proper way of figuring out how many generations separate you from someone?

Edit: Hmm, maybe not. It also says this:

The child of your first cousin is your "first cousin once removed" because the one generation separation represents one "removal". You and the child are still considered first cousins, as your grandparent (this child's great-grandparent), as the most recent common ancestor, represents one "degree".

So I guess you were right, since our last common ancestor would have been *their* grandparent, meaning we are still first cousins despite the generation difference. I guess that's where the once removed matters.

I was reading the technical definitions of "degrees" and "removals" as they apply to cousins and was trying to figure out exactly what the relationship is between me and some family members. I assume they are some type of cousin, because they are first cousins of my parents. But based on the definitions I was reading, I couldn't quite figure it out.

So if I have a relative whose mother was my grandfather's sister, what is that relative to me?

Thanks.

Lentil, beans and sunflower are the examples.

 

You can just go to the garden shop, and ask for 'lentil', or 'beans' or 'sunflower'.

Oops, somehow I glazed over that in your post!

Thanks!

they may not be able to penetrate through solid latex or polyurethane, but as the article pointed out there are sometimes manufacturing defects in condoms that could produce microscopic holes, but its still hard to say whether it is this that contributes to the small failure rate or if it is all just improper condom use and/or slippage, breakage, etc

Well, I understand that manufacturing defects are a different story altogether. My original question was referring to the myth (?) that latex condoms have naturally occurring holes, i.e. that *all* condoms would have this issue.

A fast growing plant or big flower (lentil, beans or sunflower) is impressive enough...

What's a good example of that?

I found one article that showed that some condoms do in fact let through small amounts of virus, but the exposure is several magnitudes of order smaller than what would be experienced without a condom. So... use condoms.. no sense in playing russian roulette with extra bullets in the chamber.

 

http://www.ncbi.nlm..../pubmed/9132983

 

full text

 

Background:: Because of the possible presence of small holes, the effectiveness of condoms as barriers to virus transmission is controversial.

 

Goals:: To determine the proportion of condoms that allow virus penetration and the amounts of virus that penetrate.

 

Study Design:: A sensitive, static test was used to evaluate different condom types as barriers to a small virus, including brands with or without lubrication and ones of different materials. The test included some physiologic‐based parameters and some parameters that exaggerated expected actual use conditions.

 

Results:: Under test conditions, 2.6% (12 of 470) of the latex condoms allowed some virus penetration; the median level of penetration was 7 × 10−4 ml. Lubricated condoms performed similarly to nonlubricated ones. Polyurethane condoms yielded results higher than but not statistically different from those for latex condoms.

 

Conclusions:: Few condoms allowed any virus penetration. The median amount of penetration for latex condoms when extrapolated to expected actual use conditions was 1 × 10−5 ml (volume of semen). Thus, even for the few condoms that do allow virus penetration, the typical level of exposure to semen would be several orders of magnitude lower than for no condom at all.

 

 

But what about the point made that viruses are larger than electrons, or water molecules, or air molecules, and none of these things can escape from a condom?

Venus fly trap? That will certinly impress a 4 year old

Actually, yes! I mentioned a Venus fly trap when we were going into the arboretum, and my nephew suddenly seemed obsessed with seeing one. He asked about it several times but I don't think they had one there. But is it possible to grow them? I know you can sometimes buy them (I used to want one when I was little too, and I think Kroger sometimes sold them!). But do you keep them indoors? If so, how do you feed them? I don't imagine my sister has a lot of flies in her house.

And if I remember correctly, I believe the seeds my nephew picked up were called Columbine flowers. The flower was yellow, I remember that much.

A child is impatient, you must find something that grows quickly.

Peas.

No commercial but in some shops they sell amusing puppet heads made of natural fiber with growing vegetation in place of hair. Very funny and instructive. I'll try to find a link.

 

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something similar to Mr Box Head here

Hmm, good point. About how long would it take for most flowers to grow?

This weekend I went to the arboretum with my 4-year old nephew and he found the free seeds that they were giving away to grow flowers. He took a pack and seemed interested in doing it, so I thought I might try to do this with him as a way to show him how to plant and grow a flower. Except the seeds he got seemed like they were fairly complicated to grow, with instructions for different seasons and different times of day.

So I'm wondering if someone could suggest a type of flower that could easily be grown by itself in a small pot, something that I could let him plant and water perhaps once or twice a day, without much more maintenance than that. Just a little "starter" plant, so to speak.

Thanks.

I was reading the article on Natural Family Planning on Wikipedia just now and I came across this sentence:

"In 2003 BBC's Panorama claimed that Vatican is intentionally spreading lies that HIV virus can pass through the membrane of the condom."

No other comments are made, so I'm a little confused. I had actually heard a long time ago that latex condoms have naturally occurring holes through which HIV *can* pass (since the purpose of condoms aren't necessarily to prevent disease, but to prevent pregnancy, since sperm *can't* pass through the holes). But given the above statement, I'm unclear now. Can anyone clarify please?

Thanks.

Edit: I found the transcript of the BBC program and here's a statement from it:

"The most authoritative recent report is by the US National Institute of Health which concluded: "In tact condoms are essentially impermeable to the smallest sexually transmitted virus, and that the consistent use of male condoms protects against HIV/AIDS transmission."

Assuming that's true, I can't believe I've thought otherwise for so long. I'm not even sure where I heard that anymore.

It is, in my opinion, absolutely correct to say that a book falls faster than a sheet of paper due to its larger mass.

Hmm, that's interesting. I mean, I understand that mass isn't the *only* factor, but this seems like one of those things where the "smart" answer is to say "The mass of the objects has nothing to do with why the book falls faster than the paper." In other words, it's the example given to people to prove to them that mass *doesn't* affect the rate at which an object falls, or to show them something neat about physics that goes against their natural assumption.

In a way, are you saying that the "over-corrected" answer is actually wrong as well, and a person's intuitive assumption that the mass does matter is actually right?

I know the lesson that if you were to drop a book and a sheet of paper, the book hits the ground first, not because of its weight or its mass, but because of air resistance. So I was reading this website that attempts to explain it: http://www.physicscl...wtlaws/efar.cfm

and was a little confused by this paragraph, with the relevant phrase bolded:

In fact, objects will continue to accelerate (gain speed) until the air resistance force increases to a large enough value to balance the downward force of gravity. Since the elephant has more mass, it weighs more and experiences a greater downward force of gravity. The elephant will have to accelerate (gain speed) for a longer period of time before their is sufficient upward air resistance to balance the large downward force of gravity.

Now, I understand the very basics behind how two objects will fall at the same rate in a vacuum, regardless of weight or mass. But when we are not speaking in terms of a vacuum, I thought it was still wrong to say that the reason the book falls faster is because of its weight or mass. However, the above quote seems to directly implicate weight and mass as factors for why the elephant falls faster than the feather.

So what is correct? Is it really wrong to say that a book hits the ground before the sheet of paper because of its weight or mass? Doesn't that have *anything* to do with it? If not, what does the above quote mean? Is the website wrong or am I just misunderstanding?

Thanks.

Similar to my earlier question about history books, I was hoping some of you can give me some recommendations for good books that cover politics in general. I'd like to understand the history of the U.S. parties and how they've changed over the past two centuries to become what they are today. And as far as outside the U.S., I'd love to read something about how the political systems have or haven't worked in other countries, such as why things are different and apparently successful in Europe, but many countries in Africa are failed states, etc.

It's sort of a broad scope, but maybe there are some books out there that covers such a general topic.

Thanks.

A good outline to start with would be the following Wiki Timeline, with some seemingly unbiased explanation of hundreds of different issues. I didn't go through much of this, but suspect there are many references, naming books, authors/historians, where the information has come from. If there is a particular period, subject or event your interested in, I might be able to come up with some related books on that topic.

 

 

http://en.wikipedia.org/wiki/Timeline_of_United_States_history

Thanks, I'll look into some of that!

I was wondering if anyone could recommend a good book or two that covers a broad period of US history (preferably all the way from its founding to the present century) and a book that covers world history in a similar scope, or at least the last couple of centuries. Basically, a general summary of history, government, wars, etc., nothing that focuses too much on any one issue or conflict. Are there any books like this, outside of classroom textbooks?

Thanks.

"Either I will roll a 6 the next time I roll the dice, or I will not. Therefore the probability that I roll a 6 is 50%."

 

How about that one? To take it a step further, what are the odds that you can correctly guess the outcome? Are your odds of correctly guessing 50%?

That's a great analogy. The next step of my argument was going to move to that point, i.e. which possible god are we referring to. But maybe you've shown me that it's not good to separate the two propositions.

Ok, it makes a lot more sense to me now. My reason for asking was because I was trying to formulate an argument. It's religious in nature but I don't want to turn this thread into anything other than a discussion of statistics, but I'd like to give the statement and see if it can be said that the answer is 50/50:

"That a god exists or does not exist is either true or false. Therefore, there is a 50/50 chance of either answer being correct."

Now, given what was discussed about likelihood, how would we apply that in a case like this, where there is a definite answer, but we may never actually know the answer? Does the answer to this proposition amount to nothing more than a guess? Or can certain facts be counted as making one or the other option more likely?

Or is this just an age-old discussion that will never submit itself to this type of analysis?

Generally for guessing a correct answer the probability of people getting it right is different than 50-50, depending on the question and the people. Often it is more than 50-50, but sometimes it is less. For example, "Does the earth orbit the sun?" They can guarantee getting a 50-50 chance of getting the correct answer by flipping a coin and saying yes for heads and no for tails.

I see. Is there a name for this, where an either/or answer doesn't really give a 50/50 chance, or is it not as big of a deal as I seem to think it is?

Just because there are two possibilities doesn't imply a 50-50 chance. This is only true if there are two equally likely possibilities.

Ah, that makes sense. So, generally speaking, it's wrong to say that the chances of someone getting a yes/no question right is 50/50?

Hi everyone. I have something of a vague question to ask, so I'll try to make it as coherent as possible. I assume that with a perfectly balanced coin, for example, there really is a 50/50 chance of getting either heads or tails each time.

But my question deals with situations that may have extenuating circumstances. For example, let's say you ask somebody a physics question. The possible outcomes are that they will either know the answer or not know the answer. So is it safe to say that there is a 50/50 chance that they will either know it or not know it?

What if we are told that the person in question is a physicist? It may be impossible to calculate precise odds, but is it correct to say that the possibility of giving a right or a wrong answer is no longer 50/50, even though only one of those two outcomes is possible? Or am I not making a proper distinction between something here?

Finally, is there a technical name for this kind of phenomenon?

Thanks!

The cube-square law is basically a limit for scaling things up or down as-is. Scaling things up for example, you increase body mass and muscle mass as cube, but surface areas as squares.

I thought it was muscle mass that increase by the square? Or is it that mass increases by the cube, and the surface area of these same things increase by the square? So the muscle mass is cubed, but the muscle surface area is squared? If so I think I misunderstood that originally quote I had above.

Yes, exactly. You could tell the difference using different colored lights. What makes the shirt yellow depends on the shirt in question.

Ok, it's all sinking in now. I would try this experiment if I had access to all these colored lights, but first just a hypothetical situation. Let's say you have two different yellow shirts:

Shirt #1: In the dark (no white light), you shine a red light on the shirt. The spot where the red light is shining now makes that portion of the shirt look red. This means the shirt is yellow because it is reflecting red and green light (when white light is present).

Shirt #2: Again, in the dark (no white light), you shine a red light on the shirt. The spot where the red light is shining now makes that portion of the shirt look black. This means the shirt is yellow because it is reflecting yellow light (when white light is present).

Given the above, I have three questions:

1. Is it possible to get both of these results with two different shirts? Or can it only be one or the other all the time?

2. If it is possible, what does each of the two cases mean for the shirt? What do the cases say about how the shirt was made, or what makes it look yellow to us?

3. If it is possible, why would there even be two different ways to produce a yellow shirt? Again I guess this comes down to how shirts are actually manufactured. Are they made with yellow-reflecting dyes, or with red/green-reflecting dyes, or both? If both, why are there two methods to do the same thing?

If I can't see the yellow shirt in the dark, wouldn't that suggest that it's only subtractive color? <-- it is. And whether I shine white light or red/green light on it, it doesnt matter. If I shine blue light on it, it should stay invisible.

What do you mean by "invisible"? If you shine blue light on a yellow shirt, wouldn't it be black? Or do you mean "invisible" in the dark, i.e. it would appear black in the dark?

But if you shine red or green light on it, wouldn't that change it somehow? If you shine just red, would the shirt now look red (if it's reflecting red and green light)? Or would it still appear black if the shirt is only reflecting yellow light?

This is why I'm still confused about what exactly is making us see yellow on the shirt. I understand that our eyes can tell the difference between yellow light and red/green light combined, but still, there has to be an answer to what is producing the yellow shirt, doesn't there? Either it's reflecting yellow light, or it's reflecting red/green light.

Would shining just a red light or just a green light on the shirt answer this question?