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Chemistry / Re: How is a hydrometer used to measure sugar content in wine?

« on: 19/02/2018 00:51:23 »

Here is a photo of a refractometer...


41Sqe1gDGsL._SX342_.jpg (17.62 kB . 342x365 - viewed 16440 times)

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Physiology & Medicine / Re: Could a placebo effectively replace an antipsychotic?

« on: 18/02/2018 20:53:44 »

Good for you!!!

The mind is an incredibly powerful thing.  Placebos are very much like hypnotism in that if one BELIEVES strongly enough, then great things can happen.  However, I have to agree with wolfekeeper.  To rely solely upon the placebo effectiveness of any medical treatment is inherently dangerous and irresponsible. 

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Physiology & Medicine / Re: Is erectile dysfunction evidence of dopamine impairment?

« on: 16/02/2018 20:53:42 »

... and, evan_au, don't forget the one thing none of us can escape, or correct ... age.

There have been some studies done many years ago that not only pointed at age as a major cause of ED, but they also provided a plausible evolutionary justification...

For a species to produce strong, healthy, vibrant offspring it is preferable for the male, and the female for that matter, to be of an age that would be considered "young".  In an article by FOX News https://www.shadygrovefertility.com/blog/diagnosing-infertility/does-sperm-quality-really-decrease-as-men-age/, the University of Otago announced that "a recent sperm-aging study (was compiled that included) 90 studies from more than 30 countries, scientists confirmed that there are “consistent age-related declines” in the quantity of semen, the health of sperm, and sperm’s ability to perform. While the research did not say at what specific age sperm starts declining, it mentioned that other studies have found consistent deterioration for certain sperm traits after men turn 35 or 40."

So, even evolution is out to get us as we age.   

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General Science / Re: What radiation protective clothing is needed in case of a meltdown?

« on: 11/02/2018 15:10:41 »

As far as protective clothing? 

Wear whatever would be comfortable as you escape the area as quickly as possible.

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Plant Sciences, Zoology & Evolution / Re: How many research subjects do you need for a study to be statistically valid?

« on: 10/02/2018 18:30:12 »

To have confidence that your study results are representative of the larger population, it is important that you have a large number of randomly-selected subjects in each study group, relative to the estimated population size. The larger the sample size, the less the margin of error.  The following link, www.surveysystem.com/sscalc.htm will provide you with a Sample Size Calculator, but a reasonably good approximation is the simple expression 1/n².

For example:  Say you want a confidence level of 95%, and you want the margin of error to be 6.5%, or 0.065, then...

                              sample size = 1/n², where n = margin of error.
                                                  = 1/(0.065)²
                                                  =  236 participants

What was the confidence level of the study Ms. Fugazza performed?  Most researchers use a confidence level of no less than 95%.  At 95%, and only citing 12 subjects, her margin of error would be an enormous 29 (28.29 to be exact).