the effect of wind speed on social distancing
We computationally investigate the effect of wind speed on social distancing. For a mild human cough in air at 20○C and 50% relative humidity, we found that human saliva-disease-carrier droplets may travel up to unexpected considerable distances depending on the wind speed. When the wind speed was approximately zero, the saliva droplets did not travel 2 m, which is within the social distancing recommendations. However, at wind speeds varying from 4 km/h to 15 km/h, we found that the saliva droplets can travel up to 6 m with a decrease in the concentration and liquid droplet size in the wind direction. [Physics of Fluids]
Superspreading events are ill-understood and difficult to study […] Individual patients’ characteristics play a role as well. Some people shed far more virus, and for a longer period of time, than others, perhaps because of differences in their immune system or the distribution of virus receptors in their body. […] Singing may release more virus than speaking, which could help explain the choir outbreaks. People’s behavior also plays a role. Having many social contacts or not washing your hands makes you more likely to pass on the virus.
We know most people get infected in their own home. A household member contracts the virus in the community and brings it into the house where sustained contact between household members leads to infection. But where are people contracting the infection in the community? I regularly hear people worrying about grocery stores, bike rides, inconsiderate runners who are not wearing masks…. are these places of concern? Well, not really. In order to get infected you need to get exposed to an infectious dose of the virus; based on infectious dose studies with other coronaviruses, it appears that only small doses may be needed for infection to take hold. Some experts estimate that as few as 1000 SARS-CoV2 infectious viral particles are all that will be needed (ref 1, ref 2). Please note, this still needs to be determined experimentally, but we can use that number to demonstrate how infection can occur. Infection could occur, through 1000 infectious viral particles you receive in one breath or from one eye-rub, or 100 viral particles inhaled with each breath over 10 breaths, or 10 viral particles with 100 breaths. Each of these situations can lead to an infection. […] We still do not know whether a person releases infectious material in feces or just fragmented virus, but we do know that toilet flushing does aerosolize many droplets. Treat public bathrooms with extra caution (surface and air), until we know more about the risk. […] A single cough releases about 3,000 droplets and droplets travels at 50 miles per hour. A single sneeze releases about 30,000 droplets, with droplets traveling at up to 200 miles per hour. If a person is infected, the droplets in a single cough or sneeze may contain as many as 200,000,000 (two hundred million) virus particles which can all be dispersed into the environment around them. […] A single breath releases 50 - 5000 droplets. Most of these droplets are low velocity and fall to the ground quickly. There are even fewer droplets released through nose-breathing. Importantly, due to the lack of exhalation force with a breath, viral particles from the lower respiratory areas are not expelled. Unlike sneezing and coughing which release huge amounts of viral material, the respiratory droplets released from breathing only contain low levels of virus. […] Speaking increases the release of respiratory droplets about 10 fold Speaking increases the release of respiratory droplets about 10 fold; ~200 virus particles per minute. Assuming every virus is inhaled, it would take ~5 minutes of speaking face-to-face to receive the required dose. […] Remember the formula: Successful Infection = Exposure to Virus x Time. […] In meat processing plants, densely packed workers must communicate to one another amidst the deafening drum of industrial machinery and a cold-room virus-preserving environment. There are now outbreaks in 115 facilities across 23 states, 5000+ workers infected, with 20 dead. […] Weddings, funerals, birthdays: 10% of early spreading events. […] infection events were indoors, with people closely-spaced, with lots of talking, singing, or yelling. The main sources for infection are home, workplace, public transport, social gatherings, and restaurants. This accounts for 90% of all transmission events. In contrast, outbreaks spread from shopping appear to be responsible for a small percentage of traced infections. [Erin Briomage]
Coronavirus is going to make film shoots more expensive. […] To manage the on-set health and safety measures, studios are expected to hire “COVID coordinators” who will lead staffs of 10 to 15 people on smaller movies, according to one production source. For bigger shoots, that staff could be 30 people or more. […] Studios’ insurance costs are also likely to rise because of the risk of having to pause shooting for weeks when a member of the cast or crew gets sick. […] So-called intimacy coordinators, who work with actors to ensure appropriate behavior during sex scenes, may be called upon to help performers feel comfortable during other types of shooting that require people to be near each other. [LA Times]
Some film sets are talking about quarantining together so they can keep working.
it turns out that one of the biggest obstacles to dining in a restaurant, renewing a doctor’s appointment or going back to the office is the prospect of having to use a public restroom — a tight, intimate and potentially germ-infested space. […] A Texas barbecue restaurant reopened only after hiring for a new job category: a bathroom monitor, who assures that people waiting their turn are spaced well apart. In Florida, malls are installing touch-free sinks and hand dryers in restrooms before opening their doors. McDonald’s is requiring franchisees to clean bathrooms every 30 minutes. Across the country, businesses are replacing blow dryers with paper towels, decommissioning urinals that now seem too close together, and removing restroom doors to create airport-style, no-touch entrances. […] The Aut-O-Rama Twin Drive-In theater in North Ridgeville, Ohio, reopened this week with 10 portable toilets added to the eight existing stalls. On its marquee facing the highway, the theater touted the advantages of outdoor, in-car movie watching: “Social Distancing Since 1965.” [Washington Post]
The purpose of a phase 1 clinical trial is to establish whether or not the drug or vaccine being investigated is safe. It’s not designed to test for efficacy. That being said, the trials can still provide some insights into the potential of the drug or vaccine to treat patients.
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world’s daily carbon emissions fell 17% in April […] total emissions this year will be between 4% and 7% lower than 2019’s total […] Almost half of the world’s emissions reductions last month came from a drop in transportation pollution, as people confined to their homes drove less. Reduced air travel only accounted for 10% of the emissions drop. [study]
Their brand new Full Metal Jacket is indeed made mostly of copper, a known virus-killing material for generations […] 15 kilometers of copper fiber is put into each jacket, in a production process that takes a full week to create […] Available in two colors from Vollebak, for $1095.
