Jake writes:

Hello to any and all TWiVvim who may be reading this,

In episode 421, at about 1:44:34, Dickson claims ‘they don’t do [spaceship noises while in space] on Star Trek’, and I’m just going to drop this link here:


(I’m a mathematician by training who got interested this whole ‘tiny little danger critter’ thing back in graduate school when I wrote my dissertation on the mathematics of crop epidemics, and I keep hoping for more plant-related topics on the TWi-sphere, hint hint hint)

Thanks for making so many good podcasts,


Anthony writes:

Concerning the discussion of zoonotic disease in TWiV 421, I believe that it’s noted in the Natural History of Infectious Disease by Burnet and White, that the species for most of its history existed as small, widely-dispersed groups.  This would mean that — as for pathogens our ancestors were a market just not worth developing — disease generally would be zoonotic.  The exceptions were vertically transmitted or vertically spread. (An example given for vertical spread is kissing of infants by care-givers.  Though not Norman Rockwell, fecal contamination is just as apt.)  Taken in — with the appropriate antibodies — along with mother’s milk — these entities could co-exist peacefully and perhaps not even count as pathogens.  Was it in this way that Polio has been with us so long and is the reason why there is no animal analog?

To go on to do the high-wire act of taking a speculation as an assumption and then going on to speculate some more, might there be some sort of Second Amendment in Evolution with pathogens as a militia?  In both cases, “well regulated” is pivotal.


John writes:

Three follows-up.

  1. In TWiV 421 an emailer questioned the statement that Earth’s rotation has slowed by 6 hours over historic times.  The 6 hour figure is not the change in day length (SI units radians per second).  It is the integral of rotation speed change over millennia (SI units radians).  If Earth had not slowed its rotation since Rome was founded, it would be twisted at about a 90 degree angle to its present position, but the day would still be close to 24 hours long.


  1. In or near TWiV 419 you discussed inconsistent terminology in a paper. There is a solution used in other fields: require the list of references to include a review of terminology. Virology papers could state early on, for example, “Terminology follows Flint et al. (2015).”  The reader could look there to find out exactly what “permissive” means.  While a top tier journal might be unable to expand papers by a sentence and a reference, less dense journals could ask reviewers to enforce this practice.
  1. In TWiV 421 somebody asked what happens to ads in archived podcasts.  Old episodes of the Nature podcast recently got ads that were not present when they were made.  I don’t endorse this practice, but it is a reminder that history can be rewritten.  We have always been at war with Eastasia, and Vincent has always been nice to Dickson.

P.S. Here is a vignette on the success of virology.

A Chinese friend went to grad school here and did a postdoc in biology at MIT 25 years after Vincent.  When she saw my shirt with a vaccine bottle on it she read it and asked, “what is poliomyelitis?”  My explanation may have been the first time I said “polio” out loud since high school, and she hadn’t heard of it in 16 years in America.  I thought to myself, “previous generations of scientists did such a good job, their reward is being forgotten.”

John writes:

Dear Vincent and Twivestigators,

There seems to be some confusion about the “Earth’s Rotation is Slowing” pick from TWiV 420.

The authors mention that their analysis found an increase in the length of the mean solar day (lod) at an average rate of +1.8 ms per century which is less than the predicted figure of +2.3 ms per century.

To simplify slightly; the difference between a length of day now and a length 1000 years ago is of the order of 20ms. However, the day-by-day cumulative effect of each lengthened day is about an hour for 1000CE and about 7 hours for 500BCE (according to their equation 1.5). A day today and a day 2700 years ago have slipped ~7 hours out of sync if you compared the position of the rotation of the earth vs the position of the sun (I think).

Because they can calculate the start/end times of ancient eclipses with a high degree of confidence and they have ancient local records that indicate when they occurred in local time, they (apparently) can use the difference between historic and calculated figures to extract some information about what the actual change in the spin rate is.

The historically measured “rate changes” differ from the “rate changes” given by the theoretical tidal model.

None of this really contradicts other studies (Prof. John Wells, “Coral Growth and Geochronology”, Nature 197, 948-950, 9 March 1963) using daily and annual growth rings on ancient fossilised coral to calculate ancient day lengths and the larger number of shorter days in ancient solar years. It just adds some more direct data into the mix.

Radiolab had an excellent 13 minute piece explaining about the coral/day-length discovery with paleontologist Neil Shubin, Field Museum’s Chief Curiosity Correspondent Emily Graslie and Field Museum’s Collections Manager Paul Meyer.

I submit it as a listener pick…


“we discover that our world is full of ancient coral calendars. Each one of these sea skeletons reveals that once upon a very-long-time-ago, years were shorter by over forty days. And astrophysicist Chris Impey helps us comprehend how the change is all to be blamed on a celestial slow dance with the moon. “

I don’t have a biology background but I love the TWiX family. I going to attempt Vincent’s Virology Course in the new year just to get a better handle on the language of the podcast.

Thanks and Regards,

John Mullin,



(The forecast for today is unseasonably pleasant: Mostly dry with sunny spells in places though cloud will increase to produce some patchy drizzle near coasts later on this afternoon. Highs of 7 to 9 degrees C with light south to south-east winds (10-20kmph), fresher on coasts.)

P.S. Be nice to Dickson

Michael writes:

Enjoying your podcast here in Rochester, NY. Temp outside is 0 degrees C. Light flurries.

On a recent podcast, someone raised the question of inapparent infection in mumps, given the recent outbreaks at SUNY New Paltz and SUNY Geneseo. We received a recent alert from our local health department regarding diagnosis of mumps, and this tidbit came up, thanks to UpToDate:

Inapparent infection — In contrast with these classic manifestations, asymptomatic infection occurs in 15 to 20 percent of cases, and only nonspecific or predominantly respiratory symptoms are seen in up to 50 percent of cases in whom the diagnosis of mumps is not usually made [7,35,36]. Inapparent or subclinical infections are more frequent in adults, while parotitis is most common in children between the ages of two and nine years

Happy New Year to all of you, and I really enjoy your podcasts.

Michael G. Martin, MD

Rochester, NY

Patricia writes:

Hi TWiVolios,

I actually don’t have a science comment for you this time, just two follow-ups from the last two team episodes (417 and 418).

1) Thee vs. Thou – I guess science fiction junkies aren’t always also fantasy/alternate history junkies, although I suppose if one spent a lot of time reading a bible one might also have internalized how these words work. “Thou” is the familiar form of “you,” singular, used as the subject of a sentence – “Thou art my best friend” or “Couldst thou pass the peas?” – while “thee” is the familiar you used as the direct/indirect object of the sentence – “Hark! I will pass the peas to thee!”. Thy and thine, incidentally, are roughly equivalent to your (as in your peas) and yours (the peas are yours). Modern English has merged thee and thou into the formal “You” for all instances (which is why we’ve always said “your Majesty” not “thy Majesty”), but has kept the same formatting for things like “she” vs. “her”, for example. To tie it all into a common TWiV theme, though, we really suffer for a lack of the plural “you” like German has. I’m for “y’all” and “all y’all” – I started using them when I learned German and realized how useful it was to have a way to distinguish between one “you” and many “you”‘s.


2) You asked what podcasts we listeners also listen to – I’ve sent in recommendations for picks before, but here are some more: “The History of Rome” and it’s spiritual successor “The History of Byzantium”, as well as the “Revolutions” podcast done by the same podcaster who did History of Rome. I’m getting a kick out of “The History of English” (might be explained by the same love of fantasy and language that makes Thee and Thou make sense to me) and and also “The British History Podcast”. I enjoyed both iterations of “Serial” that Rich mentioned, I listen to NPR’s “TED Radio Hour,” and I periodically peruse BBC for educational podcasts like their “Life Scientific” that I mentioned before. And of course, I’m addicted to the TWiX casts and Audiommunity (better get Kathy to say that one).

That’s all for now! Happy science-ing, everyone!


P.S. in one of your Curiosity Stream ads (yup, I listen to them) you refer to Edward Snowden as a former director of the NSA – probably a slip of the tongue, but just in case I figured that should get cleared up. He used to work for the CIA, but I’ve not ever heard of him directing any particular governmental agency.

Patricia Thibault, PhD

Postdoctoral Fellow, Lee Lab

Department of Microbiology

Icahn School of Medicine at Mount Sinai

Ann Skalka writes:

I enjoyed the discussion about proper terminology for cells infected with silent  Mavirus.  Thought you might be interested in a term coined by Jan Svoboda in 1963.  He isolated rat cells transformed with a strain of RSV. No virus was produced by the rat cells when in culture, but virus was produced if the cells were injected into chickens.  He called these rat cells “virogenic”, with lambda “lysogenic” in mind, but mindful of the distinctions.

I am learning a lot writing my retrovirus book

Mohammad writes:

Dear TWiV team,

This is Mohammad, your MERS-CoV correspondent from Saudi Arabia. I would like to congratulate you all for a very successful year (not bad for an even year, Dr. Racaniello). Wish you all a more successful 2017.

2016 carried great TWiVs as usual. Personally, the interview with D.A. Henderson was the most inspirational and ranks highest in this season. As requested in a previous episode, other podcasts that I listen to frequently include, (Nature Biotechnology Podcast), (Hidden Brain), (Radiolab), and most podcasts produced by microbe.tv.

I have two follow ups:

On TWiV 420 entitled “Orthogonal vectors”, the use of the term orthogonal was discussed. I would like to add one more example for its use applied through regulatory settings. Regulatory agencies use this term frequently in the context of describing the need of use of a second/third technique to confirm the findings of the first one. For example, protein aggregation (a nasty protein instability problem) is typically evaluated by manufacturers using multiple technologies (size-exclusion chromatography, Dynamic light scattering, and analytical ultracentrifugation, as an example) where two techniques are used orthogonal to the first one. Here are two examples from FDA (http://www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation/guidances/ucm386366.pdf) ( http://www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation/guidances/ucm291134.pdf ).

My second follow up concerns episode TWiV 413 entitled “Partnerships not parachutes”. In this episode, the many advantages of using camel vaccine against MERS-CoV were discussed, however, this discussion was followed by skepticism by some of your esteemed guests about the acceptance of such vaccine among Saudi people, especially breeders of racing camels. Personally, I don’t see how they came up with that conclusion. Lets see what the WHO statistics say about Saudi citizen’s compliance with vaccines ( http://www.who.int/gho/countries/sau.pdf?ua=1 ). DTP 3 immunization among 1-year-olds is nearly 100 %, Measles immunization among 1-yr-olds is 98 % (compared to 96 % coverage in the Netherlands, http://www.who.int/gho/countries/nld.pdf?ua=1, and 91 % in the United States of America http://www.who.int/gho/countries/usa.pdf?ua=1 ).

Two points. One, Saudis strongly believe in the power of vaccines. The scars caused by smallpox are still seen in the faces of the elderly. Two, I really don’t think Saudis love their camels more than their newborn babies.

About the racing camels issue. Let us suppose for the sake of argument that no racing camel owner agreed on vaccinating his expensive camel, those kinds of camels are rare, they are expensive for a reason, and I think herd immunity would take care of that. This brings me to the recently announced news about a MERS-CoV vaccine trial on camels going to be held soon ( http://www.jenner.ac.uk/new-mers-vaccine-programme ) ( http://www.spa.gov.sa/viewstory.php?lang=en&newsid=1568326 ). The vaccine was developed in the Jenner Institute, the University of Oxford through a joint collaboration with King Abdullah International Medical Research Center (KAIMRC), Riyadh, Saudi Arabia. The dates of the trial were not announced yet, but i guess it will begin within the next two-three months. I will keep you all posted with the results.

Now, let’s switch gear to a more serious matter, WEATHER. It is snowing in Saudi ,,, again ,,, for the third consecutive year!! (see attached pictures). Not only that, but we officially have “lakes” now ( see the following YouTube link for a newly formed one https://www.youtube.com/watch?v=X0pw_ritRR8 ).

One last thing. Many moons back, TWiV team used to leave a 30-60 seconds segment at the very end of most episodes where we (the listeners) could hear the team discussing the title of the episode. I really miss that, and wish this customary act would come back again. At least for the very creative ones. Just a thought.

Anyhow, extremely sorry for the lengthy email. I just had so many things to talk about.

My name is Mohammad Alsenaidy, and I am a TWiVoholic.







Lenn writes:

Hi Vince,

I listened to TWIV 419 and during your discussion of the Current Biology article about the mummy that had smallpox DNA I remembered a book from a few years ago titled Pox Americana: The Great Smallpox Epidemic of 1775-82, by Elizabeth Fenn.  Apparently, contemporaneous with the American Revolution, there was a massive epidemic of Smallpox that covered most of the western hemisphere.  Anyway, I thought you guys and your listeners would find it interesting.


Chris writes:

Hello again, TwiV team!

I fear I may be a bit late to be lucky #23, but I know that I cannot win if I do not play.  The weather here in Central Ohio was a very nice spring day, with the high hitting somewhere just short of 20°C with an hour or so of full sunlight.  It recently finished raining and the temperatures are supposed to fall back to a warm winter for the rest of the year.

Anyway, I was inspired by the podcast recommendations in episode 421 to share some of my other favorites outside the microbe.tv family.  (If you only have time to share one, Far Lands or Bust is the one to pick)

  • People Behind the Science: interviews about the lives of current scientists (I mentioned this in a previous e-mail, if my sent mail folder is accurate)
  • Far Lands or Bust: a YouTube series of a man’s journey to the end of the world in an old version of Minecraft.  It now comes in both podcast and video flavors.  Host Kurt J. Mac discusses gaming news, answers listener questions, and—often the best part—discuss space news.  Kurt is an avid fan of astronomy and rocket launches, so both the launch itself and details about the mission are discussed whenever they happen.  This series is also a long-term fundraiser for Child’s Play charity, which gives toys, books, and games to children in hospitals.  I gave this the longest description because after I somehow found FLoB around 5 years ago, I followed some of the people that Kurt recommended, and that started a long chain of recommendations that eventually lead me into TWiV and podcasts.
  • Track Changes: two guys discuss the life of a company they founded in NYC.  It has little relevance to my life, but the excellent chemistry between the hosts and short episodes keep me listening to each new episode and the topics often turn out to be surprisingly interesting
  • Accidental Tech Podcast: three guys discuss the tech industry (but mostly all things Apple)
  • The Scientific Odyssey: it’s all about how what we know as science came into existence.  Currently, they are discussing the shift from a geocentric to a heliocentric model of the universe and, more broadly, how science began to emerge as a distinct discipline from natural philosophy.
  • 99% Invisible: they tell interesting stories about all kinds of things that you likely would not know about, so it’s a surprise every week

Even listening at 2x speed, sometimes I get more new episodes in a week than I can keep up-to-date on, so I have to pick and choose which episodes to “Mark as played” and which to actually listen to.  My usual triage is:

  1. Short (<1hr) episodes
  2. TWiX episodes, usually TWiP followed by the others
  3. Whichever ones have the most interesting show notes

Thanks for giving me all these great podcasts,
— Chris

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