Month: July 2020

• 

  Crew Dragon is shown docked to the Harmony module on the International Space Station. [credit: NASA ]

Weather permitting, SpaceX's Crew Dragon spacecraft will splash down in the Gulf of Mexico on Sunday. Forecasters are closely watching conditions due to Hurricane Isaias but are hopeful the mission will find calm seas and light winds offshore from the Florida Panhandle.

Unlike the Apollo missions, which returned to Earth in the Pacific Ocean, NASA and SpaceX chose to target a splashdown near the Florida Peninsula. The main reason they did this is to get crews more quickly back to their homes, near Houston, after a spaceflight.

However, landing Dragon near Florida has another advantage for SpaceX. By splashing down in the Gulf of Mexico or nearshore waters of the Atlantic Ocean, a SpaceX recovery boat can transport the Crew Dragon vehicle back to the company's facilities at Cape Canaveral Air Force Station within days. This has become all the more important after a recent announcement that NASA will allow SpaceX to begin reusing its Crew Dragon spacecraft early next year.

Enlarge / A masked pedestrian crosses an empty street at a usually busy intersection in the Central Business District on February 3, 2020, in Beijing, China. (credit: Getty | Keven Frayer)

Reports of influenza and a host of other infectious diseases have plummeted as the COVID-19 pandemic has driven people into lockdowns.

In many places, social distancing measures aimed at curbing the spread of the new coronavirus may be smothering the spread of other infectious diseases at the same time. But, in other places, the pandemic may simply be masking disease spread, as people may avoid seeking care for more routine infections while health care systems stretched thin by the pandemic may struggle to conduct routine, surveillance, testing, and reporting.

Some of the resulting declines are dramatic. Countries across the Southern Hemisphere have reported much lower numbers of influenza than usual. Australia, for instance, began 2020 with a relatively high level of flu—reporting around 7,000 lab-confirmed cases in both January and February. But the outbreak crashed in March, with reports of only 229 cases in April, compared with nearly 19,000 in April 2019, as noted by the New Scientist.

Enlarge / Long lines called "cloud streets" forming off the edge of Antarctic sea ice. (credit: NASA EO)

One of the lesser-known scientific complications that makes assessing human-caused climate change a hassle is that it isn’t all about greenhouse gases. Emissions of aerosols—tiny atmospheric particles from a variety of sources that scatter sunlight back to space, for example—have acted to offset a portion of the human-caused warming. And unlike long-lived greenhouse gases, aerosols wash out of the atmosphere quite quickly and leave no historical record. That makes reconstructing aerosol levels going back before the Industrial Revolution a challenge.

To improve and cross-check estimates of past aerosol levels, researchers have gotten creative. A new study led by Isabel McCoy at the University of Washington uses the fact that the skies around Antarctica are close to free from human-caused aerosol pollution to set a new pre-industrial baseline.

Aerosols have a cooling influence through both direct (scattering sunlight) and indirect (modifying clouds) effects. In this case, the researchers are looking at the latter by using satellite cloud data. Specifically, they calculate the number of cloud droplets per cubic centimeter based on measurements of droplet size and cloud thickness. Because aerosols can act as condensation nuclei around which droplets form, they tend to lead to higher levels of smaller droplets.

Enlarge / Skeletal stem cells are shown here in red. (credit: Noriaki Ono)

Stem cells hold the promise of helping us repair tissues damaged by disease or injury. But outside of bone marrow stem cells, the practice remains largely a promise, as we're just starting clinical trials to determine if we can use these cells effectively. But that hasn't stopped people from offering stem cell "treatments" with no basis in evidence. Many of the clinics that offer these services are based overseas, leading to what's been termed "stem cell tourism." But a number take advantage of ambiguities in Food and Drug Agency regulations to operate in the United States.

A new survey of doctors suggests that a surprising number of their patients are using these services—sometimes with severe consequences. And many doctors don't feel like they're prepared to deal with the fallout.

Widespread interest

The work focuses on neurologists, who specialize in treating diseases of the nervous system. These include diseases like Parkinson's and multiple sclerosis, for which there are few effective treatments—although stem cells have undergone some preliminary tests in the case of Parkinson's. Given the lack of established options, it wouldn't be surprising if these patients turned to therapies that haven't been established, like those involving stem cells.