[Lex Computer & Tech Group/LCTG] Meeting Reminder: John Snow and the Cholera Epidemic of 1854, presented by Jerry Slate. On Wednesday, April 6, 2022, at 10AM ET. Lexington Computer and Technology Group Online Meeting via Zoom

Fri Apr 8 06:25:03 PDT 2022

 Thanks, Jerry for the updated information.
-- Bob Primak

    On Friday, April 8, 2022, 08:46:08 AM EDT, Jerome Slate <slatemd at comcast.net> wrote:  

  Dear Group,
 The question was raised as to why the cholera epidemics in Europe ended and why it has persisted in Haiti.  A brackish water source is the environmental reservoir. It comes out of this from time to time and colonizes fresh water where it is not well-suited to survive. A subsequent epidemic can be an entirely new event. 
 A longer discussion is below:
 Jerry

V. cholerae is a natural inhabitant of brackish riverine (situated on a river or riverbank), estuarine, and coastal waters, and only a subset of strains are known to be pathogenic to humans. Recent studies have begun to uncover a very complex network of relationships between V. cholerae and other sea dwellers, and the mechanisms associated with the occurrence of seasonal epidemics in regions where cholera is endemic are beginning to be elucidated.

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There are numerous factors that affect V. Cholerae persistence, survival, and pathogenic potential.  Several physicochemical conditions affect V. cholerae populations in the natural environment, such as water temperature, salinity, oxygen tension, sunlight, rainfall, pH, and the availability of trace elements and chemical nutrients. Although there are strong correlations between the changes in the physicochemical conditions in the environment of V. cholerae, the mechanisms by which some of them affect the population dynamics of V. cholerae remain unknown.

The known environmental hosts of V. cholerae include algae, shellfish, chironomid egg masses, fish, waterfowl, amebae, and most ubiquitously, copepods (small crustaceans).

Human Epidemics

Due to their low initial concentrations of choleragenic V. cholerae, human carriers can show no symptoms of the disease.  In the early epidemic period, a similar process happens; this time the patients will show symptoms of cholera and will shed strongly adapted and highly virulent epidemic clones. 

It is thought that when the number of predators of V. cholerae significantly outnumbers the total of toxigenic clones, epidemics come to a collapse. For example, an increase in the number of bacteriophages that thrive on V. cholerae in both water and stools is directly correlated with the termination of cholera epidemics.

Nonetheless, other environmental factors likely also play a role in the self-limiting nature of cholera epidemics.  In its natural environment V. cholerae encounters two main predators: bacteriophages and protozoa. It has also been found that some antagonistic bacteria inhibit the growth of V. cholerae.  
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 On 4/5/2022 10:47 AM, Jonathan Goode wrote:

    (NOTE: Repeated Reminder with contents unchanged.) 

Our Zoom Meeting ID is 972 6146 0830. Detailed instructions for joining us are at the end of this message.

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April 6, 2022
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John Snow and the Cholera Epidemic of 1854, presented by Jerry Slate

John Snow (1813 – 1858) was a British physician who became interested in the transmission of cholera. At the time, airborne transmission of disease, miasma, was the accepted model for cholera. When Snow showed his data on the cholera epidemic of 1854 (in a manner not previously seen), there was much resistance in the scientific community to a paradigm shift.
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Below are our plans for Upcoming Meetings. For more schedule information, please refer to https://wiki.toku.us/doku.php?id=lctg_speaker_schedule  We will continue to have an online presentation (almost) every Wednesday until it is prudent for us to resume meeting in person.

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April 13, 2022
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Craig Fields on DARPA (not to be recorded at speaker's request) Dr. Craig I Fields will be coming to the Computer Group primarily to discuss his role as Director of DARPA.

He received his BS degree from the Massachusetts Institute of Technology and his Ph.D. from the Rockefeller University. He served on the faculty of Harvard University; he was the Director of the Defense Advanced Research Projects Agency (DARPA); he was the Chairman and Chief Executive Officer of the Microelectronics and Computer Technology Corporation (MCC). He is a Member of the Defense Science Board, joining the Board in 1993 and Chairman of the Board for 14 years thereafter.
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April 20, 2022
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Potpourri
 Space Update (conclusion) George Gamota
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SPECIAL NOTE - Links to many of our previous sessions are available online at http://lctg.toku.us/, thanks to the diligence of Steve Isenberg. This includes our sessions

   - Downdraft Radar Technology, presented by Dr. Jim Evans. https://youtu.be/bZpFPjNnNBA
   - Quantum Mechanics, part 1: https://youtu.be/m1vdpQuUzaw
   - Virus Package Update  https://youtu.be/hw9JEz9GIJE 
   - Lagrangian Points, especially L2. https://youtu.be/LNOF_mexw-o 

Virus Follow-up: Browser Guards. https://youtu.be/Uy9N8rb0zUk 

   - Space Update:  https://youtu.be/NWw-xQM5PxA 
   - Managing File Size, special presentation from New Zealand by our group’s former leader, Allan Sherman https://youtu.be/o2V4GAm_YHo      

If this email wasn't addressed to you and you would like to join the group, or if you have a friend or colleague who might also be interested in joining, it's easy.  Ask them to go to the group's wiki page at http://LCTG.toku.us and follow the simple instructions under "Join the Email List".  By being a member of the group you'll get reminders of upcoming meetings and infrequent related messages. No advertising.  The list is tightly managed.

Membership is free and given that all meetings are using Zoom you only need to be connected to the Internet to join. It's ok to join from anywhere you can get a decent Internet connection.

We, the Lexington Computer and Technology Group, will meet Wednesday at the usual 10AM Eastern Time, BUT ONLINE, using the Zoom Video Conferencing Application, facilitated by Steve Isenberg. 

There is an instruction page at https://toku.us/zoomish but note that the URL and phone number shown are examples.

To join our meeting, sometime after 9:45 AM on Wednesday, choose one of the following options:

   - If you have the Zoom application installed, start it and join meeting with ID 972 6146 0830
   - From your browser, go to: https://zoom.us/j/97261460830
   - >From your smartphone, tap this: +16468769923,,97261460830
   - From a “dumb” telephone, call 1 646 876 9923 and enter meeting ID: 972 6146 0830 

Once the connection is established, you may need to locate and use the on-screen controls that turn on the sound and the video. You should be able to see and hear others and they should be able to see and hear you, if you have a camera and microphone (each of which you can unmute selectively).

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