Wikipedia:Reference desk/Archives/Science/2018 November 6

= November 6 =

Contraceptive method efficiency assessment: typical vs perfect use
In above, there is a link to Calendar-based_contraceptive_methods. That article says that such methods have a 25% pregnancy rate per year in typical use. I was about to post an angry note that this is terrible efficiency; the sex ed classes I had in France insist that using calendar-based methods work if you want to get pregnant but should not be relied on to avoid getting pregnant.

Then I looked at other contraceptives and saw that the pregnancy rate per year in typical use is around 20% for (male or female) condoms, and even hormonal methods are not really close to 0 but more like 5%-ish, see table in Birth_control. That leads me to two questions:
 * 1) Are calendar methods actually as efficient as others? The stats for both condom, spermicide and "fertility awareness" in the table look fairly similar (20%/year typical use, 5%/year perfect use). (I guess sex ed messages to teenagers have to be simple and "get him to wear a condom" is easier than "get him to wait four days", but I distinctly remember a harangue against those.)
 * 2) How do you even get a statistic for "perfect use"? I get how you can get typical use (survey the population for "has been using method X for at least a year" and "got pregnant last year" and take the ratio), but perfect use is another thing. Tigraan Click here to contact me 14:00, 6 November 2018 (UTC)
 * I'm kind of surprised that we don't have an article at Marquette method (hint, hint for those interested) which claims 98-99% effectiveness according to Marquette University. We do have an article at Billings method which is similar. I imagine the perfect use numbers come from studies where the couples involved chart their cycles. shoy (reactions) 14:10, 6 November 2018 (UTC)
 * I actually know two of the children of John and Evelyn Billings. There are three others that I know of. There are many grandchildren. I make no claim about what this means. HiLo48 (talk) 03:11, 7 November 2018 (UTC)
 * It's briefly mentioned in Fertility awareness Nil Einne (talk) 19:22, 6 November 2018 (UTC)
 * I recall a university biology teacher discussing the costs of the various forms of contraception, saying "natural methods" are the most expensive, because you'll have a baby nine months later. ←Baseball Bugs What's up, Doc? carrots→ 11:47, 7 November 2018 (UTC)
 * The percentages mentioned in the article are probably cherry-picked or misinterpreted. Abductive  (reasoning) 17:31, 7 November 2018 (UTC)
 * Not sure about the figures in the various individual articles come from but the figures in the table in birth control methods seem to mostly come from this ref [//www.contraceptionjournal.org/article/S0010-7824(11)00049-7/fulltext]. You can get the preprint version of that article here [//www.ncbi.nlm.nih.gov/pmc/articles/PMC3638209/]. While this article [//www.cdc.gov/mmwr/preview/mmwrhtml/rr6205a1.htm] is also given as a ref, most of the figures in the table seemed to be from the earlier article. BTW, I read Tigraan's initial post more carefully and wonder if there is some confusion which has sort of been addressed in follow-ups but not in a clear fashion. Fertility awareness does not simply refer to calendar based methods but also symptoms-based methods. Nil Einne (talk) 16:09, 8 November 2018 (UTC)
 * I agree, the term "calendar method" is horribly outdated. If you want to be accurate, you can call them sympto-thermal methods instead. shoy (reactions) 18:58, 9 November 2018 (UTC)
 * Or use George Carlin's idea about a less-than-foolproof contraceptive brand: "Baby-Maybe". ←Baseball Bugs What's up, Doc? carrots→ 21:51, 9 November 2018 (UTC)
 * As I understand it, and this seems to be supported by our articles sympto-thermal methods are not calendar methods. They are a form of fertility awareness or fertility based methods but they use both symptoms and temperature hence "sympto" and "thermal". Sympto-thermal are generally considered a subset of symptoms-based methods since they are using symptoms but they will need the thermal aspect to be sympto-thermal. (I suspect there are sources which treat sympto-thermal as a distinct set from symptom based methods i.e. symptom based means no use of basal body temperature.) Calendar-based contraceptive methods are another subset of symptoms-based methods, the subset that only uses a single symptom namely the first day of bleeding. From what our articles say, I think some sources may exclude calendar based methods from symptoms-based methods completely because only one minor symptom is used. Symptoms-based methods is instead reserved for more sophisticated methods. And I think home computerised Fertility testing is also starting to become a thing.  To be clear while there may be some used of a calendar in some of the other methods, what I'm saying is that Calendar-based contraceptive methods generally refers to methods which only use the first day of ovulation and a calendar rather than more information like cervical mucus or basal body temperature or position of the cervix. Note also that while the Calendar-based contraceptive methods article does say "", from what I can tell this means the term fertility awareness is restricted to  the normal meaning of the rhythm method rather than the rhythm method being used to include more sophisticated methods. I.E. Affirming what I said earlier, I see little evidence that calendar-based methods is used much for more sophisticated methods at least by decent sources.  For these reasons fertility based methods is probably the clearest term which includes calendar based methods and more sophisticated symptom based methods including sympto-thermal methods. (I earlier said fertility awareness, but forgot this can refer to a specific method per our article.)  Nil Einne (talk) 13:13, 10 November 2018 (UTC)
 * See the explanation at . 2A02:C7D:CAA6:A200:4471:4D17:DD5C:D292 (talk) 17:24, 13 November 2018 (UTC)

What are the intracellular concentrations of electrolytes of the giant squid cardiomyocyte?
I want to contrast the differences between neurons and cardiomyocytes in humans with the differences in cardiomyocytes in the squid. I am aware squid have two-chamber hearts. However, I am having trouble finding information on *squid* *cardiomyocytes* because I keep getting all this irrelevant information on the giant squid axon contaminating my search results and barely any information on the giant squid cardiomyocyte. Help? Yanping Nora Soong (talk) 19:21, 6 November 2018 (UTC)
 * Squids like octopuses have three hearts: in the squid are two branchial hearts and one systemic heart. The branchial hearts pump blood (which is white not red like ours) to the gills where oxygen is taken up. Blood then flows to the systemic heart where it is pumped to the rest of the body. See Clay J.R., Paydarfar D., Forger D.B. A simple modification of the Hodgkin and Huxley equations explains type 3 excitability in squid giant axons. J. R. Soc. Interface. 2008;5:1421–1428 cited in Optogenetic versus Electrical Stimulation of Human Cardiomyocytes: Modeling Insights. DroneB (talk) 23:13, 6 November 2018 (UTC)
 * I doubt that any researcher has looked into this in that sort of detail. One can probably assume that the electrolytes are the same as other species cardiomyocytes, or that the ratios when comparing other species neuronal electrolytes to their cardiomyocytes is similar. Abductive  (reasoning) 17:28, 7 November 2018 (UTC)
 * That sounds like a good assumption when comparing say, a pig and human, but not an invertebrate cephalopod and a human. After all the squid giant axon has resting potential -60 to -70 mV whereas human neurons and cardiomyocytes are between -90 and -95 mV. There are many important differences between the neuronal action potential and the cardiac action potential in mammals. What are the differences in cephalopods? Yanping Nora Soong (talk) 20:17, 8 November 2018 (UTC)
 * I took a cursory look in Google Scholar. It doesn't seem like there has been a lot of work on squid cardiomyocytes. They use the giant axon because it is giant. Your question is better asked by emailing university professors who work in the field. Abductive  (reasoning) 21:28, 8 November 2018 (UTC)