India's test created 400 pieces of debris, risk to Space Station: NASA

Denser places, assumed by many to be more conducive to the spread of the coronavirus that causes COVID-19, are not linked to higher infection rates, say researchers.

The study, led by Johns Hopkins University, published in the Journal of the American Planning Association, also found that dense areas were associated with lower COVID-19 death rates.

"These findings suggest that urban planners should continue to practice and advocate for compact places rather than sprawling ones, due to the myriad well-established benefits of the former, including health benefits," says study lead author Shima Hamidi from Johns Hopkins Bloomberg School of Public Health in the US.

For their analysis, the researchers examined SARS-CoV-2 infection rates and COVID-19 death rates in 913 metropolitan counties in the US.

When other factors such as race and education were taken into account, the authors found that county density was not significantly associated with county infection rate.

The findings also showed that denser counties, as compared to more sprawling ones, tended to have lower death rates--possibly because they enjoyed a higher level of development including better health care systems.

On the other hand, the research found that higher coronavirus infection and COVID-19 mortality rates in counties are more related to the larger context of metropolitan size in which counties are located.

Large metropolitan areas with a higher number of counties tightly linked together through economic, social, and commuting relationships are the most vulnerable to the pandemic outbreaks.

According to the researchers, recent polls suggest that many US citizens now consider an exodus from big cities likely, possibly due to the belief that more density equals more infection risk.

Some government officials have posited that urban density is linked to the transmissibility of the virus.

"The fact that density is unrelated to confirmed virus infection rates and inversely related to confirmed COVID-19 death rates is important, unexpected, and profound," said Hamidi.

"It counters a narrative that, absent data and analysis, would challenge the foundation of modern cities and could lead to a population shift from urban centres to suburban and exurban areas," Hamidi added.

The analysis found that after controlling for factors such as metropolitan size, education, race, and age, doubling the activity density was associated with an 11.3 per cent lower death rate.

The authors said that this is possibly due to faster and more widespread adoption of social distancing practices and better quality of health care in areas of denser population.

The researchers concluded that a higher county population, a higher proportion of people age 60 and up, a lower proportion of college-educated people, and a higher proportion of African Americans were all associated with a greater infection rate and mortality rate.

Twitter has hinted that it is planning a paid subscription platform that can be reused by other teams in the future.

The news that the micro-blogging platform is building a subscription platform with a team codenamed "Gryphon" resulted in Twitter stock rising over 8% on Wednesday.

Twitter revealed its plan via a job listing that seeks a full-stack senior software engineer in New York to join "Gryphon".

Interestingly, Twitter "edited" the job listing once the news broke, removing the part about "Gryphon" and any mention of their internal team or their subscription feature. The listing said the company is looking for an Android engineer to "work on a bevy of backend engineering teams to build components that allow for experimentation to deliver the best experience possible to all of our users".

Later, Twitter users noticed that the company restored the earlier job listing that mentioned the upcoming subscription platform and "Gryphon".

A spokesperson for Twitter told CNN on Wednesday that it's only a job posting, not a product announcement.

This is not the first time Twitter has thought of a paid product. 

In 2017, it sent out a survey to users and a preview of what a premium offering of its TweetDeck app might look like, including breaking news alerts and more analytics, according to The Verge.

"We're conducting this survey to assess the interest in a new, more enhanced version of Tweetdeck. We regularly conduct user research to gather feedback about people's Twitter experience and to better inform our product investment decisions, and we're exploring several ways to make TweetDeck even more valuable for professionals," a Twitter spokesperson had said at that time.

Aboard Air Force One, Jan 6: US President Donald Trump threatened sanctions against Baghdad on Sunday after Iraq's parliament called on US troops to leave the country, and the president said if troops did leave, Baghdad would have to pay Washington for the cost of the air base there.

"We have a very extraordinarily expensive air base that's there. It cost billions of dollars to build, long before my time. We're not leaving unless they pay us back for it," Trump told reporters on Air Force One.

Trump said that if Iraq asked US forces to leave and it was not done on a friendly basis, "we will charge them sanctions like they've never seen before ever. It'll make Iranian sanctions look somewhat tame."