Wednesday, September 30, 2020

Neuralink in a Dozen Pigs


In a far-ranging chat with Kara Swisher, Elon Musk talked about sustainable energy, brain implants, the stupidity of the press, and more. He gave a casual update on the “Three Little Pigs” demo of Neuralink's 1024-channel chip, finally admitting that his lofty goals are in a “very, very primitive stage”:

Elon Musk: You can make people walk again. You could solve extreme depression or anxiety or schizophrenia or seizures. You could give a mother back her memory so she could remember who her kids are, you know. Basically, if you live long enough, you’re going to get dementia of some kind. And you’ll want to have something to help you. [NOTE: here, he didn't acknowledge the potential for advancements in biological treatments for dementia.]

Kara Swisher:  Could it program in empathy? Or other things? Do you imagine that being part of this? [LAUGHTER] Or hey you could—

EM: You could technically program anything. So empathy is probably a good one.

KS: So where are we in doing this?

EM: So where we are right now is we’re still in a very, very primitive stage. Where thus far we’ve had a lot of successful implants in pigs. And we now have a pig that has had an implant that’s working well and it’s been there for over three months. And we now have implanted about a dozen pigs. And the sensors are working well. A large part of a pig brain is about its snout. So you can literally rub the pig on its snout and we can detect exactly where you touch the snout. [NOTE: “Yeah, that's called somatotopic mapping,” said John Hughlings Jackson in 1886.]


Listen to the podcast: Elon Musk: ‘A.I. Doesn’t Need to Hate Us to Destroy Us’ 

In a conversation with Kara Swisher, the billionaire entrepreneur talks space-faring civilization, battery-powered everything and computer chips in your skull.


Bonus!! Musk on Trump:

Kara Swisher: Do you like him? Are you voting for him?

Elon Musk: [SIGHING] I mean, I’m — to be totally frank I’m not — I mean, I think — let’s just see how the debates go. You know?

KS: That’s going to be your thing, the debates?

EM: Well, I think that is probably the thing that will decide things for America.

KS: Why is that?

EM: I think people just want to see if Biden’s got it together.

KS: Mm-hmm. And if he does?

EM: If he does, he probably wins.

 

He hasn't yet tweeted about the disgraceful dumpster fire... 

 




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Monday, August 31, 2020

The Mundane Spectacle of the Three Little Pigs



“This Neuralink is implanted in the region of the brain that uh where where the snout the snout is located which is actually quite a large part of the pig's brain.” 1

Elon Musk held a press event (product demo) to make grandiose claims about the Neuralink 1024-channel brain implant currently under development by his start-up.

Three pigs were unveiled, all healthy and happy: Joyce (the one without an implant), Dorothy (who formerly had an implant), and Gertrude, the star of the day with her snout boops. The crowd applauded, impressed at this monumental accomplishment. However, recording spike trains from the brains of animals is as old as time. And actually, wireless Implantable Neuroprosthetics in Pigs is so 2011...2


The title of this post in TNW said it best:

I was excited for Neuralink. Then I watched Elon Musk’s stupid demo
“Here’s the one fact you need to know: Neuralink's actual device is less capable than similar medical BCIs already on the market. The big claim to fame here is that Neuralink hopes one day to bring this technology to the masses.”

And really, invasive intracranial technology is likely to obsolete by the time the requisite advances in neural decoding would occur (if ever). As Kording Lab member Ari Benjamin told BBC News:
“Once they have the recordings, Neuralink will need to decode them and will someday hit the barrier that is our lack of basic understanding of how the brain works, no matter how many neurons they record from.

Decoding goals and movement plans is hard when you don't understand the neural code in which those things are communicated.”

Another winner in the snark department was MIT Technology Review, with:

Elon Musk’s Neuralink is neuroscience theater
“...Neuralink has provided no evidence that it can (or has even tried to) treat depression, insomnia, or a dozen other diseases that Musk mentioned in a slide. One difficulty ahead of the company is perfecting microwires that can survive the ‘corrosive’ context of a living brain for a decade. That problem alone could take years to solve.

The primary objective of the streamed demo, instead, was to stir excitement, recruit engineers to the company (which already employs about 100 people), and build the kind of fan base that has cheered on Musk’s other ventures...”

The cult of Musk is indeed cheering, in a rather credulous fashion (e.g., Why Neuralink Will Change Humanity Forever).


Footnotes

1 It's actually correct that the representation of the snout in pig somatosensory cortex occupies a disproportionately large portion of the cortex.

2 Borton et al. (2011) reported on their “complete neural prosthetic developmental system using a wireless sensor as the implant, a pig as the animal model, and a novel data acquisition paradigm for actuator control.” At that time, the system had 'only' 16 channels, but the field as a whole has evolved since then.


ADDENDUM (Sept 1, 2020):
from Neuralink Progress Update, Summer 2020



An implantable device will solve all these problems by correcting aberrant electrical signals. And drive summon your Tesla telepathically too!

  • Save and replay memories!
  • Super-Vision! (ultraviolet or infrared)
  • Use a computer by thought alone!

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Thursday, July 30, 2020

What Color is Your Mental Parachute?

Aphantasia and Occupational Choice


NOTE: This isn't a real test of visual imagery. Click HERE for the Simple Aphantasia Test, which assesses whether (and how well) you can imagine pictures in your mind's eye.


Do you prefer to learn by studying material that is visual, auditory, verbal (reading/writing), or kinesthetic (“by doing”) in nature? A massive educational industry has promoted the idea of distinct “learning styles” based on preference for one of these four modalities (take the VARK!). This neuromyth has been thoroughly debunked (see this FAQ).

But we humans clearly vary in our cognitive strengths, and this in turn influences our choice of career. This should come as no surprise.

A recent study queried the occupational choices of self-selected populations of people at the extremes of visual imagery abilities: those with Aphantasia (n=993 male/981 female) or Hyperphantasia (n=65 male/132 female). This was assessed by their scores on the Vividness of Visual Imagery Questionnaire (VVIQ). There was also a control group with average scores on the VVIQ, but they were poorly matched on age and education.


Fig. 4 (Zeman et al., 2020). Percentage of participants with aphantasia and hyperphantasia reporting their occupation as being:
1 = Management, 2 = Business and financial; 3 = Computer and mathematical/Life, physical, social science; 4 = Education, training, and library; 5 = Arts, design, entertainment, sports and media; 6 = Healthcare, practitioners and technical.


As expected, people with fantastic visual imagery were more likely to be in arts, design, entertainment, and media, as well as sports (an excellent ability to imagine a pole vault or swing a bat would be very helpful). People with poor to no visual imagery were more likely to choose a scientific or mathematical occupation. These categories are rather broad, however. For instance, “media” includes print media. And artists and photographers with Aphantasia certainly do exist.

The study had a number of limitations, e.g. washing out individual differences and relying on introspection for rating visual imagery ability (as noted by the authors). There are more objective ways to test for imagery, but these involve in-person visits. Although the authors were circumspect in the Discussion, they were a bit splashy in the title of their paper (Phantasia–The Psychological Significance Of Lifelong Visual Imagery Vivdness Extremes). And the condition of “Aphantasia” existed long before it was named and popularized. But these researchers have caught the imagination of the general public, so to speak:
The delineation of these forms of extreme imagery also clarifies a vital distinction between imagery and imagination: people with aphantasia–who include the geneticist Craig Venter, the neurologist Oliver Sacks and the creator of Firefox, Blake Ross–can be richly imaginative, as visualisation is only one element of this more complex capacity to represent, reshape and reconceive things in their absence.

Reference

Zeman A, Milton F, Della Sala S, Dewar M, Frayling T, Gaddum J, Hattersley A, Heuerman-Williamson B, Jones K, MacKisack M, Winlove C. (2020). Phantasia–The Psychological Significance Of Lifelong Visual Imagery Vivdness Extremes. Cortex. 2020 May 4; S0010-9452(20)30140-4.

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Tuesday, June 30, 2020

Traces of Fear in Aphantasia

When reading a vivid story that describes a shark attack, do you imagine yourself in the ocean, seeing the dorsal fin approach you?
“...sun glints off the waves / suddenly a dark flash / in the distant waves / maybe it was a shadow / you turn to the beach / more people are pointing / they look anxious / looking back out to sea / a large fin / slices the surface / moving closer...”



Or is your “mind's eye” — your visual mental imagery of the evocative scene ⁠— essentially a blank?



early warning: picture of snake below

One's subjective internal life of thinking, perceiving, imagining, and remembering belongs to oneself and nobody else. [Brain scanning is still not a mind reader.] An increasing number of media reports (and scientific studies) have shined a light on this fact: the mental life of one person differs from that of another, sometimes in startling ways. It's always been that way, but now it's out in the open.

The cat is out of the bag.



When reading that sentence, did you have a fleeting mental picture in your mind's eye? Maybe it was clear, maybe it was hazy. Or maybe you saw no visual image at all... if that was the case, you might have a condition known as Aphantasia, the inability to voluntarily generate mental imagery. This is a normal variant of human experience, albeit an uncommon one.

What are the “consequences” of having Aphantasia? You may be more likely to choose a scientific or mathematical occupation, although artists and photographers with Aphantasia certainly exist. Aphantasia is often associated with poor autobiographical memory (diminished ability to recall the past episodes of your life).

Does Aphantasia affect your emotional reactions to ordinary experiences like looking at pictures or reading a story? If visual imagery is important for having an affective response to the shark story, would people with Aphantasia show physiological (bodily) signs of emotion while reading? Wicken and colleagues (2019) asked this question by comparing the skin conductance response (sweaty palms) evoked by reading vs. looking at pictures. This was a pilot study reported in a preprint (not yet peer reviewed).

If visual imagery is necessary for an affective response to evocative stories, then A-Phantasics should have diminished (or absent) skin conductance responses (SCRs) compared to Typical-Phantasics. In contrast, SCRs to unpleasant pictures should not differ between the two groups, because the picture-viewing experience doesn't require imagery. However, it's still possible that imagery-based elaboration (or verbal elaboration, for that matter) could amplify the SCR, especially since each picture was presented for 5 seconds.




For the reading condition, stories were presented as sequential short phrases (to match reading speed across subjects). The control conditions weren't well-matched, unfortunately. This was especially true for Stories, where reading the task instructions served as the neutral comparison condition (instead of reading a neutral story).


Participants

The participants were 24 individuals with intact imagery (based on the Vividness of Visual Imagery Questionnaire and binocular rivalry priming1 scores within the typical range) and 22 self-identified Aphantasics (who were older, on average, than the control participants).2 For the Aphantasia group, seven (out of the original 29) were excluded because their VVIQ or priming scores exceeded the cut-off.


Results

For the Pictures (Perception) condition, the physiological response to Unpleasant vs. Neutral stimuli was not significantly different for the two groups. Incidentally speaking, the skin conductance level (SCL = SCR) was quite variable, as shown in the shaded portion of the graph below.



Adapted from Fig. 1D (Wicken et al., 2019).  Left: Aggregated progressions of baseline-corrected SCL across the duration of the frightening photos sequence (sampled as average across 5 sec time bins). Right: Mean and standard error across time bins.


The Stories were another story... For the Stories (Imagery) condition, the Aphantasic group did not show an elevated SCL for the scary stories, unlike the controls.



Adapted from Fig. 1B (Wicken et al., 2019).


Or as the authors suggested, “[Aphantasia] is associated with a flat-line physiological response to frightening written, but not perceptual scenarios, supporting imagery’s critical role in emotion.”

I'd say “flat-line” is a little judgy, with the semantic implication that the Aphantasics were dead or something.

I'd like to see subjective ratings of emotion (affect and arousal) for the Pictures and Stories, especially since the primary means of identifying people with Aphantasia is based on subjective report. Nonetheless, this is an intriguing finding, with additional evidence forthcoming (or so I imagine)...


Footnotes

1 See: Is there an objective test for Aphantasia? Binocular rivalry priming can be a useful “objective” measure of aphantasia (Keogh & Pearson, 2018), but it's not necessarily diagnostic at an individual level.

2 Mean age = 33.7 yrs for Aphantasia, mean = 23.0 for controls. I don't know why they didn't recruit age-matched controls from the community, other than the convenience of recruiting university students.


Reference

Wicken M, Keogh R, Pearson J. (2019). The critical role of mental imagery in human emotion: insights from Aphantasia. bioRxiv. 2019 Jan 1:726844.




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Sunday, May 31, 2020

The COVID Stress Scales



Danger. Deprivation. Xenophobia. Contamination. These are some of the fears related to COVID-19. Scores of COVID questionnaires have popped up recently to assess fear, anxiety, stress, and depression related to the novel coronavirus and its massive disruption to daily life. Most are freely available for use as research tools, but few have been validated and peer reviewed.

The COVID Stress Scales (CSS) developed by Taylor and colleagues (2020) were recently published in the Journal of Anxiety Disorders. The authors propose a new COVID Stress Syndrome, and present evidence that the CSS subscales are intercorrelated (which is suggestive of a “coherent” condition).

To develop the CSS, representative samples of people in Canada (n=3,479) and the US (n=3,375) completed a 58-item survey on Qualtrics. Factor analysis identified five subscales...
  1. COVID danger and contamination fears
  2. COVID fears about economic consequences
  3. COVID xenophobia
  4. COVID compulsive checking and reassurance seeking
  5. COVID traumatic stress symptoms

...and limited the questionnaire to 36 items. I'll note that “fears about economic consequences” were restricted to a lack of supplies at grocery stores and pharmacies, rather than fears of crushing debt, eviction, hunger, and homelessness because of unemployment.

One can view this new syndrome as a context-related extension of OCD contamination fears, compulsive checking, and health anxiety (preoccupation with the possibility of serious illness). Indeed, convergent validity was confirmed by showing correlations with established measures of those conditions. Unique aspects of COVID Stress Syndrome not seen in other diagnoses include fears that grocery stores would run out of toilet paper,1 and especially a fear of foreigners (xenophobia). Xenophobia is promulgated by politicians and amplified by bad actors on social media and IRL. I don't think xenophobia (specifically, anti-Asian sentiment) is on the list of symptoms for any DSM diagnosis.

Basically, it seems that a coherent condition called COVID Stress Syndrome would require racist beliefs and a fear of people who are Chinese, Chinese-American, or Chinese-Canadian.2 The prevalence of COVID Stress Syndrome in their Canadian and American samples was not specified, nor was the cut-off point for such a diagnosis. Plenty of Americans are xenophobic, but they don't have bad dreams about coronavirus.

In an editorial, Taylor and Asmundson (2020) said:
It appears that people who develop COVID Stress Syndrome have pre-existing psychopathology, particularly pre-existing high levels of health anxiety and obsessive-compulsive checking and contamination symptoms. It remains to be seen whether the COVID Stress Syndrome is simply an adjustment disorder, abating once the pandemic is over, or whether it will become chronic for some individuals.

So much about COVID-19 “remains to be seen”, and this level of uncertainly is a major source of anxiety on its own.


Footnotes

1 The toilet paper question just missed the cut...included were worries about water, cleaning supplies, medications, etc. The original version also included “worry about looting & rioting.”

2 One could really say East Asian people more broadly. Or actually, anyone considered “Other”.


References

Taylor S, Asmundson GJG. (2020). Life in a post-pandemic world: What to expect of anxiety-related conditions and their treatment. J Anxiety Disord. 2020; 72:102231.

Taylor S, Landry CA, Paluszek MM, Fergus TA, McKay D, Asmundson GJG. Development and initial validation of the COVID Stress Scales. J Anxiety Disord. 2020; 72:102232.


Additional Scales (from a compendium of COVID questionnaires on Google docs)

Epidemic-Pandemic Impacts Inventory Racial/Ethic Discrimination Addendum (15 items).

COVID-19 Stressful events (13 items)

COVID-19 Concerns (9 items)

Coronavirus Stressor Survey (9 items)

CRISIS (The CoRonavIruS Health Impact Survey V0.3) - more here

Covid-19 Staff Needs and Concerns Survey (18 items)

COVID-19 Family Stress Screener (10 items)


ADDENDUM (June 1, 2020): MORE!

UCLA Brief COVID-19 Screen for Child/Adolescent PTSD

Fear of COVID-19 Scale (10 items)
Ahorsu DK, Lin CY, Imani V, Saffari M, Griffiths MD, Pakpour AH. The Fear of COVID-19 Scale: Development and Initial Validation. International Journal of Mental Health and Addiction. 2020 Mar 27:1-9.
Coronavirus Anxiety Scale (5 items)
Lee SA. Coronavirus Anxiety Scale: A brief mental health screener for COVID-19 related anxiety. Death Studies. 2020 Apr 16:1-9.




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Monday, April 27, 2020

The Noble Prize for a Life Well-Lived

In honor of a beautiful and affectionate cat.



RIP, beloved Max
April 19, 2003 April 24, 2020


So much acrimony and confusion and death...


In the true meaning of the word, Max lived a noble life.

“But he was just a cat,” you say. Yes, that's true. But he was loving and kind and selfless until the very end. He was a wonderful companion, and a great source of comfort to me (especially after my partner died in October 2018).



Max and Sandra
Feb. 2, 2017


He was cherished by previous caretakers and human friends, who showered him with gifts.



Christmas Eve, 2017




Christmas Day, 2018


But now he's gone and life continues, filled with acrimony and confusion and death.


The Very Real Threat of Trump’s Deepfake by David Frum

While reading this article in The Atlantic, I was immediately struck by how a cat could hold human values and respect human life to a greater extent than the President of the United States. Sounds absurd, doesn't it? But not really. Not any more. Here's David Frum:
April 26, 2020, was an especially manic day in the presidency of Donald Trump.  ...  something was gnawing at him. Perhaps his business troubles were weighing on him.  ...  Or perhaps Trump was still seething at the widespread ridicule of his press conference of April 23, when he suggested using disinfectant “by injection.” Or perhaps something else had shifted his mood from its usual setting of seething aggrievement to frothing fury.

Whatever the cause, between early afternoon and near 9 o’clock eastern time, Trump fired off a sequence of crazy-even-for-him tweets and retweets. He demanded that reporters be stripped of the “Noble prizes” they had supposedly been awarded for their reporting on Trump scandals, apparently conflating them with the Pulitzers—and then pretended that his misspelling of Nobel had been intentional.  ...  He retweeted an increasingly wild and weird range of supporters’ Twitter accounts.

Trump shows no compassion for the suffering around him, no sympathy for the families devastated by the loss of their loved ones, and only hollow praise for the health care workers, the bus drivers, the home delivery drivers, the grocery store clerks, and the sanitation workers who put their lives on the line every day.

Eternal optimists say “we're all in this together” while sitting at home on Zoom meetings, placing endless orders on Amazon, and fretting about their sourdough starter. I'm only marginally better, but I realize I'm privileged. {I've tried to help financially contributing to homeless organizations, a fund for unemployed hourly workers, bookstores, museums, etc.}

And obviously I'm way more pessimistic.

How does this rant honor my cat??


Case History

Max was diagnosed with intestinal lymphoma in August 2019 at the age of 16. He also had a murky ailment that made it difficult for him to eat (“his tongue is inflamed” or later, “he has a mass at the base of his tongue”), but the true cause was never confirmed. He was prescribed oral chemotherapy pills three times a week and an oral steroid (prednisolone syrup) twice daily. I declined the chemo pills, opting for quality of life for both of us. Max's oral steroid became unworkable after four doses.

This was not fair, especially after my wife suffered through Stage 4 cancer for a year.

Another vet started bimonthly / monthly injections of Depo-Medrol (methyl prednisolone) to reduce the inflammation in his mouth, and as a partial treatment for his lymphoma. It worked wonders (for a while). He ran up and down stairs, played with his toys, and jumped over the red chair!

He started getting worse in January. His weight was down to 9.5 lbs (4.3 kg), a 2 lb loss in two months. He was prescribed buprenorphine as needed for pain and transdermal mirtazapine as an appetite stimulant. My quest for palatable foods became more and more challenging. I spent hours walking the aisles of pet superstores.




ADDENDUM (April 28, 2020): How could I forget his stint on an all-chicken diet (KFC no skin of course or grocery store roasted chicken), which he enjoyed for a few weeks until he could no longer eat chicken...

His last regular appointment was March 9. And then the shelter-in-place orders were issued.


Pet Care During the COVID-19 Pandemic

Max's condition was getting worse. Depo-Medrol was less and less effective, and he needed injections every two weeks. The veterinary practice enacted stringent measures to protect its essential workers. In-person appointments were reserved for animals showing signs of extreme pain and suffering. Virtual Vet was used for consults and for recommending treatment plans. We had an appointment on March 27. Max was prescribed his usual meds. I picked them up curbside (calling upon arrival) and paid via contactless transaction. I watched a helpful YouTube video and then administered his subcutaneous injection of Depo-Medrol.

By April 16, I had grown desperate. The poor fellow was having a severe bout of diarrhea that lasted for days. I tried scheduling a Virtual Vet appointment and called for a refill of buprenorphine. Finally I got through and picked up more meds the next day. These included oral metronidazole, a hideously bitter and distressing medication that made his mouth foam.

He improved slightly. I was up for hours in the middle of the night, trying to coax him to eat. Some "meaty morsels" and "flaked' varieties were palatable for their gravy. I got out the food processor and whirled them into a very soft format, which he mostly rejected. “But you were just licking the gravy off these meaty morsels!” I told him. Finally I came up with a winning concoction. But this was only a palliative interlude before the inevitable.

Then I realized I'd established a Palliative Care Unit for my cat.

On April 23, I could no longer care for him myself. I brought him to the ER for severe dehydration. He had blood work and an "incidental" ultrasound, neither of which he'd had since his initial diagnosis. The results were devastating. Anemia due to suspected blood loss from his GI tract. Elevated white blood cell count (no surprise). Emerging diabetes mellitus (e.g., glucose in his urine), a known side-effect of steroid treatment. He weighed only 3.8 kg (8.4 lbs).

Most concerning was “free fluid in the abdomen and what looks like masses, possibly lymph nodes and fluid distended bowel loops.”  /  “If he does not improve in the next few days to a week, humane euthanasia should be considered given what we know.”

I picked him up and brought him home. He hated car rides much more than actual visits to the vet or treatments of any sort. Veterinary staff all loved him. The report from his ER doc even said, “Max is a very good cat.”

He was withdrawn for several hours. Then he got over it and sat on my lap in the red chair, purring. Here he is, as beautiful as ever.




The change in Max from that day to the next was astounding. He couldn't hold his head up any more. He tried to drink some water but couldn't manage to do it. I don't think any additional intervention would have improved his condition. I didn't want to wait any longer and had to act quickly.

I was fortunate to find a caring and compassionate vet who made house calls, and wasn't ridiculously overboard on COVID-19 restrictions. Some said they wouldn't enter the main living area — it had to take place outside or in the garage or in their mobile van. But Max was in a comfortable and familiar environment, at least. And then he didn't have to suffer any longer.


Max was such a sweet, loving, affectionate cat. He sought me out until the end, until his very last day when he was too weak to do so.




This is another story of love, and of loss. How we care for the most helpless among us is an enduring sign of our humanity.



MORE CAT PHOTOS below.

Read more »

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Friday, March 27, 2020

The "Six Feet Away" Rule is Woefully Inadequate

“...the rapid international spread of COVID-19 suggests that using arbitrary droplet size cutoffs may not accurately reflect what actually occurs with respiratory emissions, possibly contributing to the ineffectiveness of some procedures used to limit the spread of respiratory disease” (Bourouiba, 2020).

Dr. Lydia Bourouiba has published an important paper that updates 1930s-era models of respiratory infectious disease transmission based on the size of droplets emitted when a person breathes or talks or coughs or sneezes. Large droplets were thought to contaminate the area immediately surrounding an infected individual, because they settle before evaporating. In contrast, small droplets evaporate quickly and form residual particulates, or aerosols. However, the classification of droplet size (and therefore the mode of transmission) is not based on modern science. Yet this scheme still informs public health policy to this day.

The figure above shows a Multiphase Turbulent Gas Cloud From a Human Sneeze (Bourouiba, 2020). The puff trapped droplets of many sizes and carried them quite a long distance (23-26 feet!) while evading evaporation. Droplets that settle can contaminate surfaces. Aerosols may persist in the air for hours, depending on ambient temperature and humidity, as well as prevailing winds or airflow of indoor ventilation systems.1

Watch the educational video showing Respiratory Pathogen Emission Dynamics and you will be truly horrified!!

This newer understanding of respiratory emission dynamics has implications for mask and respiratory design, social distancing recommendations, and other public health interventions during and after the COVID-19 pandemic.”


Speaking of masks, droplets are visible after sneezing into a surgical mask (Granville-Chapman & Dunn, 2007). Although the paper was a light-hearted study appearing in the Christmas issue of BMJ, the spread of respiratory droplets is no longer a joke.




Footnote

1 A recent report by investigators in Singapore suggested the possibility of significant environmental contamination (including air vents) in the hospital rooms of SARS-CoV-2 patients (Sean Wei Xiang Ong et al., 2020). The air samples themselves were negative, however. And standard cleaning  procedures effectively decontaminated surfaces.


ADDENDUM (March 28, 2020): @SamWangPhD rightfully pointed out that sneezing is not a symptom of coronavirus-19 infection. My initial reply was that an asymptomatic individual could be strolling through a park and sneeze due to allergies. On a more scientific note, it's true that the COVID-19 symptom of coughing isn't as violent as sneezing. However:

"droplets of diameter 30 µm can have a horizontal range of up 2.5 m away from the cougher due to cloud dynamics."






References

Bourouiba L (2020). Turbulent Gas Clouds and Respiratory Pathogen Emissions: Potential Implications for Reducing Transmission of COVID-19. JAMA March 26.

Granville-Chapman J, Dunn RL. (2007). Excuse me! BMJ 335:1293.

Ong SW, Tan YK, Chia PY, Lee TH, Ng OT, Wong MS, Marimuthu K. (2020). Air, surface environmental, and personal protective equipment contamination by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from a symptomatic patient. JAMA March 4.


Thanks to @midendian and @perrymetzger for alerting me to this article.

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