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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.

Enlarge / Security updates intended to patch the BootHole UEFI vulnerability are rendering some Linux systems unable to boot at all. (credit: Aurich Lawson)

Early this morning, an urgent bug showed up at Red Hat's bugzilla bug tracker—a user discovered that the RHSA_2020:3216 grub2 security update and RHSA-2020:3218 kernel security update rendered an RHEL 8.2 system unbootable. The bug was reported as reproducible on any clean minimal install of Red Hat Enterprise Linux 8.2.

The patches were intended to close a newly discovered vulnerability in the GRUB2 boot manager called BootHole. The vulnerability itself left a method for system attackers to potentially install "bootkit" malware on a Linux system despite that system being protected with UEFI Secure Boot.

RHEL and CentOS

Unfortunately, Red Hat's patch to GRUB2 and the kernel, once applied, are leaving patched systems unbootable. The issue is confirmed to affect RHEL 7.8 and RHEL 8.2, and it may affect RHEL 8.1 and 7.9 as well. RHEL-derivative distribution CentOS is also affected.

Enlarge (credit: Tom Raftery / Flickr)

Authorities on Friday charged three people with orchestrating this month's epic hack of Twitter and using it to generate more than $100,000 in a bitcoin scam promoted by hijacked accounts of politicians, executives, and celebrities.

Federal prosecutors in San Francisco charged Mason Sheppard, 19, Nima Fazeli, 22, and an unnamed juvenile in the July 15 breach. Prosecutors in Florida, where the juvenile defendant lives, identified him as 17-year-old Graham Ivan Clark and charged him with 30 felony charges. Federal prosecutors said that Sheppard resided in the UK town of Bognor Regis, while Fazeli was from Orlando, Florida.

The three suspects stand accused of using social engineering and other techniques to gain access to internal Twitter systems. They then allegedly used their control to take over what Twitter has said were 130 accounts. A small sampling of the account holders included former Vice President Joe Biden, Tesla founder Elon Musk, pop star Kanye West, and philanthropist and Microsoft founder, former CEO, and Chairman Bill Gates.

Enlarge (credit: Tom Raftery / Flickr)

A Florida teen has been arrested and charged with 30 felony counts related to the high-profile hijacking of more than 100 Twitter accounts earlier this month.

Federal law enforcement arrested Graham Ivan Clark, 17, in Tampa earlier today, the Office of Hillsborough State Attorney Andrew Warren said. The arrest followed an investigation spearheaded by the Federal Bureau of Investigation and the Justice Department.

"These crimes were perpetrated using the names of famous people and celebrities, but they're not the primary victims here," said Warren. "This 'Bit-Con' was designed to steal money from regular Americans from all over the country, including here in Florida. This massive fraud was orchestrated right here in our backyard, and we will not stand for that."

For more than 300 years, most scientists have assumed that sperm "swim" through fluids by wriggling their tails back and forth like eels to propel themselves forward. But according to a new paper in Science Advances, this is actually an optical illusion—the result of viewing the creatures from above with 2D microscopes. New observations with 3D microscopy have revealed that human sperm actually roll as they swim, like otters, essentially corkscrewing themselves forward.

"With over half of infertility caused by male factors, understanding the human sperm tail is fundamental to developing future diagnostic tools to identify unhealthy sperm," said co-author Hermes Gadelha from the University of Bristol.

The honor of directly observing the first sperm rests with Antonie van Leeuwenhoek, a 17th-century Dutch draper with a side interest in science—specifically, building microscopes and coming up with innovative manufacturing methods to make better lenses for said microscopes. Only a few of his microscopes have survived, but they are capable of magnifying small objects up to 275 times, and historians believe some of his instruments could have achieved magnifications as high as 500 times.